<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                    FORM 10-Q


[X]   QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
      EXCHANGE ACT OF 1934

                  FOR THE QUARTERLY PERIOD ENDED JUNE 30, 1999

                                       OR

[ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
     EXCHANGE ACT OF 1934

      FOR THE TRANSITION PERIOD FROM TO FROM ____________ TO ____________


                         Commission file number 0-18169

                            IEA INCOME FUND IX, L.P.
             (Exact name of registrant as specified in its charter)


            California                                   94-3069954
 (State or other jurisdiction of                      (I.R.S. Employer
  incorporation or organization)                     Identification No.)

         444 Market Street, 15th Floor, San Francisco, California 94111
               (Address of principal executive offices)         (Zip Code)

                                 (415) 677-8990
              (Registrant's telephone number, including area code)


Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. Yes [X].  No [ ].


<PAGE>   2

                            IEA INCOME FUND IX, L.P.

                  REPORT ON FORM 10-Q FOR THE QUARTERLY PERIOD
                               ENDED JUNE 30, 1999

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                             PAGE
                                                                                                             ----
<S>        <C>                                                                                               <C>
PART I - FINANCIAL INFORMATION

  Item 1.  Financial Statements

           Balance Sheets - June 30, 1999 (unaudited) and December 31, 1998                                    4

           Statements of Operations for the three and six months ended June 30, 1999 and 1998 (unaudited)      5

           Statements of Cash Flows for the six months ended June 30, 1999 and 1998 (unaudited)                6

           Notes to Financial Statements (unaudited)                                                           7

  Item 2.  Management's Discussion and Analysis of Financial Condition and Results of Operations              10

  Item 3.  Quantitative and Qualitative Disclosures About Market Risk                                         12

PART II- OTHER INFORMATION

  Item 1.  Legal Proceedings                                                                                  13

  Item 3.  Defaults Upon Senior Securities                                                                    13

  Item 5.  Other Information                                                                                  13

  Item 6.  Exhibits and Reports on Form 8-K                                                                   14

</TABLE>



                                       2
<PAGE>   3
                            IEA INCOME FUND IX, L.P.

                                 BALANCE SHEETS

                         PART I - FINANCIAL INFORMATION


  Item 1. Financial Statements

          Presented  herein are the  Registrant's  balance sheets as of June 30,
          1999 and December 31, 1998, statements of operations for the three and
          six months ended June 30, 1999 and 1998,  and statements of cash flows
          for the six months ended June 30, 1999 and 1998.


                                       3
<PAGE>   4

                            IEA INCOME FUND IX, L.P.

                                 BALANCE SHEETS

                                   (UNAUDITED)

<TABLE>
<CAPTION>
                                                                              June 30,      December 31,
                                                                                1999           1998
                                                                             ------------   ------------
<S>                                                                         <C>            <C>
                    Assets

Current assets:
    Cash and cash equivalents, includes $641,354 at June 30, 1999 and
       $780,329 at December 31, 1998 in interest-bearing accounts            $    641,454   $    780,429
    Net lease receivables due from Leasing Company
       (notes 1 and 2)                                                            190,313        229,107
                                                                             ------------   ------------

           Total current assets                                                   831,767      1,009,536
                                                                             ------------   ------------

Container rental equipment, at cost                                            13,595,640     14,429,687
    Less accumulated depreciation                                               7,541,987      7,605,099
                                                                             ------------   ------------
       Net container rental equipment                                           6,053,653      6,824,588
                                                                             ------------   ------------
                                                                             $  6,885,420   $  7,834,124
                                                                             ============   ============
               Partners' Capital

Partners' capital (deficit):
    General partner
                                                                             $    (48,000)  $    (38,512)
    Limited partners                                                            6,933,420      7,872,636
                                                                             ------------   ------------

           Total partners' capital                                              6,885,420      7,834,124
                                                                             ------------   ------------

                                                                             $  6,885,420   $  7,834,124
                                                                             ============   ============

</TABLE>

   The accompanying notes are an integral part of these financial statements.


                                       4
<PAGE>   5

                            IEA INCOME FUND IX, L.P.

                            STATEMENTS OF OPERATIONS

                                   (UNAUDITED)
<TABLE>
<CAPTION>
                                                   Three Months Ended       Six Months Ended
                                                  ---------------------   ----------------------
                                                    June 30,  June 30,     June 30,   June 30,
                                                     1999       1998         1999       1998
                                                  ---------   ---------   ---------   ---------
<S>                                               <C>         <C>        <C>          <C>
Net lease revenue (notes 1 and 3)                 $ 256,048   $ 426,392   $ 598,792   $ 841,323
Other operating expenses:
    Depreciation                                    204,671     221,979     411,458     447,905
    Other general and administrative expenses         8,136      10,066      22,280      23,886
                                                  ---------   ---------   ---------   ---------
                                                    212,807     232,045     433,738     471,791
                                                  ---------   ---------   ---------   ---------

       Earnings from operations                      43,241     194,347     165,054     369,532
Other income (loss):
    Interest income                                   7,553      11,810      15,798      24,248
    Net loss on disposal of equipment                (5,051)    (28,283)    (66,960)    (70,007)
                                                  ---------   ---------   ---------   ---------
                                                      2,502     (16,473)    (51,162)    (45,759)
                                                  ---------   ---------   ---------   ---------
       Net earnings                               $  45,743   $ 177,874   $ 113,892   $ 323,773
                                                  =========   =========   =========   =========

Allocation of net earnings:
    General partner                               $  14,770   $  20,563   $  33,342   $  40,807
    Limited partners                                 30,973     157,311      80,550     282,966
                                                  ---------   ---------   ---------   ---------
                                                  $  45,743   $ 177,874   $ 113,892   $ 323,773
                                                  =========   =========   =========   =========
Limited partners' per unit share of net earnings  $    0.91   $    4.62   $    2.37   $    8.32
                                                  =========   =========   =========   =========
</TABLE>

   The accompanying notes are an integral part of these financial statements.




                                       5
<PAGE>   6

                            IEA INCOME FUND IX, L.P.

                            STATEMENTS OF CASH FLOWS

                                   (UNAUDITED)
<TABLE>
<CAPTION>

                                                           Six Months Ended
                                                      -------------------------
                                                         June 30,     June 30,
                                                          1999         1998
                                                      -----------   -----------
<S>                                                   <C>           <C>
Net cash provided by operating activities             $   644,268   $   845,373

Cash flows provided by investing activities:
    Proceeds from sale of container rental equipment      279,352       274,347

Cash flows used in financing activities:
    Distribution to partners                           (1,062,595)   (1,261,154)
                                                      -----------   -----------

Net decrease in cash and cash equivalents                (138,975)     (141,434)


Cash and cash equivalents at January 1                    780,429       999,900
                                                      -----------   -----------

Cash and cash equivalents at June 30                  $   641,454   $   858,466
                                                      ===========   ===========

</TABLE>




   The accompanying notes are an integral part of these financial statements.


                                       6
<PAGE>   7

                            IEA INCOME FUND IX, L.P.

                     NOTES TO UNAUDITED FINANCIAL STATEMENTS



(1)   Summary of Significant Accounting Policies

      (a) Nature of Operations

          IEA Income Fund IX, L.P. (the "Partnership") is a limited partnership
          organized under the laws of the State of California on June 8, 1988
          for the purpose of owning and leasing marine cargo containers. Cronos
          Capital Corp. ("CCC") is the general partner and, with its affiliate
          Cronos Containers Limited (the "Leasing Company"), manages the
          business of the Partnership. The Partnership shall continue until
          December 31, 2009, unless sooner terminated upon the occurrence of
          certain events.

          The Partnership commenced operations on December 5, 1988, when the
          minimum subscription proceeds of $1,000,000 were obtained. The
          Partnership offered 40,000 units of limited partnership interest at
          $500 per unit, or $20,000,000. The offering terminated on September
          11, 1989, at which time 33,992 limited partnership units had been
          purchased.

          As of June 30, 1999, the Partnership owned and operated 1,870
          twenty-foot, 634 forty-foot and 1,157 forty-foot high-cube marine dry
          cargo containers.

      (b) Leasing Company and Leasing Agent Agreement

          Pursuant to the Limited Partnership Agreement of the Partnership, all
          authority to administer the business of the Partnership is vested in
          CCC. CCC has entered into a Leasing Agent Agreement whereby the
          Leasing Company has the responsibility to manage the leasing
          operations of all equipment owned by the Partnership. Pursuant to the
          Agreement, the Leasing Company is responsible for leasing, managing
          and re-leasing the Partnership's containers to ocean carriers and has
          full discretion over which ocean carriers and suppliers of goods and
          services it may deal with. The Leasing Agent Agreement permits the
          Leasing Company to use the containers owned by the Partnership,
          together with other containers owned or managed by the Leasing Company
          and its affiliates, as part of a single fleet operated without regard
          to ownership. Since the Leasing Agent Agreement meets the definition
          of an operating lease in Statement of Financial Accounting Standards
          (SFAS) No. 13, it is accounted for as a lease under which the
          Partnership is lessor and the Leasing Company is lessee.

          The Leasing Agent Agreement generally provides that the Leasing
          Company will make payments to the Partnership based upon rentals
          collected from ocean carriers after deducting direct operating
          expenses and management fees to CCC. The Leasing Company leases
          containers to ocean carriers, generally under operating leases which
          are either master leases or term leases (mostly two to five years).
          Master leases do not specify the exact number of containers to be
          leased or the term that each container will remain on hire but allow
          the ocean carrier to pick up and drop off containers at various
          locations; rentals are based upon the number of containers used and
          the applicable per-diem rate. Accordingly, rentals under master leases
          are all variable and contingent upon the number of containers used.
          Most containers are leased to ocean carriers under master leases;
          leasing agreements with fixed payment terms are not material to the
          financial statements. Since there are no material minimum lease
          rentals, no disclosure of minimum lease rentals is provided in these
          financial statements.


                                                                     (Continued)


                                       7
<PAGE>   8

                            IEA INCOME FUND IX, L.P.

                     NOTES TO UNAUDITED FINANCIAL STATEMENTS


      (c) Basis of Accounting

          The Partnership utilizes the accrual method of accounting. Net lease
          revenue is recorded by the Partnership in each period based upon its
          leasing agent agreement with the Leasing Company. Net lease revenue is
          generally dependent upon operating lease rentals from operating lease
          agreements between the Leasing Company and its various lessees, less
          direct operating expenses and management fees due in respect of the
          containers specified in each operating lease agreement.

      (d) Financial Statement Presentation

          These financial statements have been prepared without audit. Certain
          information and footnote disclosures normally included in financial
          statements prepared in accordance with generally accepted accounting
          procedures have been omitted. It is suggested that these financial
          statements be read in conjunction with the financial statements and
          accompanying notes in the Partnership's latest annual report on Form
          10-K.

          The preparation of financial statements in conformity with generally
          accepted accounting principles (GAAP) requires the Partnership to make
          estimates and assumptions that affect the reported amounts of assets
          and liabilities and disclosure of contingent assets and liabilities at
          the date of the financial statements and the reported amounts of
          revenues and expenses during the reported period. Actual results could
          differ from those estimates.

          The interim financial statements presented herewith reflect all
          adjustments of a normal recurring nature which are, in the opinion of
          management, necessary to a fair statement of the financial condition
          and results of operations for the interim periods presented.


(2)  Net Lease Receivables Due from Leasing Company

     Net lease receivables due from the Leasing Company are determined by
     deducting direct operating payables and accrued expenses, base management
     fees payable, and reimbursed administrative expenses payable to CCC and its
     affiliates from the rental billings payable by the Leasing Company to the
     Partnership under operating leases to ocean carriers for the containers
     owned by the Partnership. Net lease receivables at June 30, 1999 and
     December 31, 1998 were as follows:

<TABLE>
<CAPTION>
                                                                      June 30,           December 31,
                                                                        1999                 1998
                                                                     ----------           ------------
<S>                                                                  <C>                   <C>
          Lease receivables, net of doubtful accounts of $60,656
            at June 30, 1999 and $75,951 at December 31, 1998         $482,612             $524,138
          Less:
          Direct operating payables and accrued expenses               178,646              177,061
          Damage protection reserve                                     49,009               51,003
          Base management fees                                          56,366               56,982
          Reimbursed administrative expenses                             8,278                9,985
                                                                      --------             --------
                                                                      $190,313             $ 29,107
                                                                      ========             ========

</TABLE>

                                                                     (Continued)




                                       8
<PAGE>   9

                            IEA INCOME FUND IX, L.P.

                     NOTES TO UNAUDITED FINANCIAL STATEMENTS


(3)  Net Lease Revenue

     Net lease revenue is determined by deducting direct operating expenses,
     base management fees and reimbursed administrative expenses to CCC from the
     rental revenue billed by the Leasing Company under operating leases to
     ocean carriers for the containers owned by the Partnership. Net lease
     revenue for the three and six-month periods ended June 30, 1999 and 1998
     was as follows:

<TABLE>
<CAPTION>
                                                            Three Months Ended                     Six Months Ended
                                                        ---------------------------           ------------------------------
                                                         June 30,           June 30,           June 30,            June 30,
                                                          1999               1998               1999                1998
                                                        --------           --------            --------          -----------
<S>                                                  <C>                 <C>                <C>               <C>
          Rental revenue (note 4)                       $409,200           $584,283            $907,290          $1,191,617
          Less:
          Rental equipment operating expenses             95,587             89,569             190,062             199,928
          Base management fees                            33,586             40,127              69,960              82,364
          Reimbursed administrative expenses              23,979             28,195              48,476              68,002
                                                        --------           --------            --------          -----------
                                                        $256,048           $426,392            $598,792          $  841,323
                                                        ========           ========            ========          ==========
</TABLE>

(4)   Operating Segment

     The Financial Accounting Standards Board has issued SFAS No. 131,
     "Disclosures about Segments of an Enterprise and Related Information,"
     which changes the way public business enterprises report financial and
     descriptive information about reportable operating segments. An operating
     segment is a component of an enterprise that engages in business activities
     from which it may earn revenues and incur expenses, whose operating results
     are regularly reviewed by the enterprise's chief operating decision maker
     to make decisions about resources to be allocated to the segment and assess
     its performance, and about which separate financial information is
     available. Management operates the Partnership's container fleet as a
     homogenous unit and has determined, after considering the requirements of
     SFAS No. 131, that as such it has a single reportable operating segment.

     The Partnership derives its revenues from owning and leasing marine cargo
     containers. As of June 30, 1999, the Partnership operated 1,870
     twenty-foot, 634 forty-foot and 1,157 forty-foot high-cube marine dry cargo
     containers.

     Due to the Partnership's lack of information regarding the physical
     location of its fleet of containers when on lease in the global shipping
     trade, it is impracticable to provide the geographic area information
     required by SFAS No. 131. Any attempt to separate "foreign" operations from
     "domestic" operations would be dependent on definitions and assumptions
     that are so subjective as to render the information meaningless and
     potentially misleading.

                                                                     (Continued)

                                       9
<PAGE>   10

Item 2. Management's Discussion and Analysis of Financial Condition and Results
        of Operations

It is suggested that the following discussion be read in conjunction with the
Registrant's most recent annual report on Form 10-K.


1)   Material changes in financial condition between June 30, 1999 and December
     31, 1998.

     During the first six months of 1999, the Registrant disposed of 231
     containers as part of its ongoing container operations. At June 30, 1999,
     77% of the original equipment remained in the Registrant's fleet, as
     compared to 81% at December 31, 1998, and was comprised of the following:

<TABLE>
<CAPTION>
                                                                                         40-Foot
                                                20-Foot              40-Foot            High-Cube
                                                -------              -------            ---------
<S>                                             <C>                  <C>                <C>
          Containers on lease:
                Term leases                        220                  88                  148
                Master leases                    1,175                 387                  822
                                                 -----                 ---                ------
                    Subtotal                     1,395                 475                  970

          Containers off lease                     475                 159                  187
                                                 -----                 ---                ------
                Total container fleet            1,870                 634                1,157
                                                 =====                 ===                =====
</TABLE>

<TABLE>
<CAPTION>
                                                                                                  40-Foot
                                                          20-Foot              40-Foot            High-Cube
                                                     ---------------       ---------------      --------------
                                                     Units        %        Units        %       Units        %
                                                     -----       ---       ----        ---      -----      ---
<S>                                                  <C>         <C>        <C>        <C>      <C>        <C>
          Total purchases                            2,327       100%       799        100%     1,653      100%
               Less disposals                          457        20%       165         20%       496       30%
                                                     -----       ---        ---        ---      -----      ---
          Remaining fleet at June 30, 1999           1,870        80%       634         80%     1,157       70%
                                                     =====       ===        ===        ===      =====       ===
</TABLE>

     During the second quarter of 1999, distributions from operations and sales
     proceeds amounted to $529,491, reflecting distributions to the general and
     limited partners for the first quarter of 1999. This represents a decline
     from the $533,104 distributed during the first quarter of 1999, reflecting
     distributions for the fourth quarter of 1998.

     The sentiment with respect to the container industry's slump over the past
     two years has turned more favorable in recent months as evidence suggests a
     turnaround is underway with respect to Asia's economic crisis. In recent
     months, economic reforms in Asia, as well as in Latin America, have begun
     to produce gradual improvement in terms of world trade, and there are
     preliminary indications that containerized trade volumes from North America
     and Europe to Asia, in particular, may be stabilizing. In addition,
     intra-Asian trade, which also has stagnated since the Asia financial crisis
     began nearly two years ago, has shown increased activity in recent months.
     These favorable signs, however, have yet to produce any significant
     positive impact on the Registrant's operating performance. In spite of the
     reduced redelivery of on-hire equipment by the ocean carriers, per-diem
     rental rates, which declined sharply over the past two years, have
     continued to soften as a result of competitive market conditions, decreased
     demand and high inventories.

     The Registrant continues to take advantage of its strong marketing
     resources in order to seek out leasing opportunities during this period in
     which seasonal factors are also influencing the increased demand. At the
     same time, it has


                                       10
<PAGE>   11

     identified specific strategies intended to strengthen on-hire volumes and
     enhance utilization of the container fleet. The short-term objective is to
     improve utilization by offering greater leasing incentives and actively
     moving surplus, off-hire equipment to higher-demand locations. While this
     short-term strategy will increase repositioning expenses, it may also
     minimize those expenses related to handling and storing off-hire
     containers. These measures will also provide the longer-term advantage of
     placing the containers where the demand is greatest.


2)   Material changes in the results of operations between the three and
     six-month periods ended June 30, 1999 and the three and six-month periods
     ended June 30, 1998.

     Net lease revenue for the three and six-month periods ended June 30, 1999
     was $256,048 and $598,792, respectively, a decline of approximately 40% and
     29% from the respective three and six-month periods in the prior year.
     Gross rental revenue (a component of net lease revenue) for the three and
     six-month periods ended June 30, 1999 was $409,200 and $907,290,
     respectively, a decline of 30% and 24% from the same respective three and
     six-month periods in 1998. Gross rental revenue was primarily impacted by a
     slightly smaller fleet size and lower per-diem rental rates. Average
     per-diem rental rates for the three and six-month periods ended June 30,
     1999 declined 9% and 8%, respectively, when compared to the same three and
     six-month periods in the prior year. The Registrant's average fleet size
     and utilization rates for the three and six-month periods ended June 30,
     1999 and 1998 were as follows:

<TABLE>
<CAPTION>
                                                            Three Months Ended             Six Months Ended
                                                           --------------------           -------------------
                                                           June 30,        June 30,     June 30,        June 30,
                                                            1999            1998         1999            1998
                                                         -----------     -----------  -----------     -------
<S>                                                      <C>             <C>          <C>             <C>
          Average fleet size (measured in twenty-foot
              equivalent units (TEU))                        5,543           6,116       5,629           6,193
          Average Utilization                                    78%             82%         77%             82%
</TABLE>


     The Registrant's diminishing fleet contributed to a 8% decline in
     depreciation expense when compared to the same three and six-month periods
     in the prior year. Rental equipment operating expenses were 23% and 21%,
     respectively, of the Registrant's gross lease revenue during the three and
     six-month periods ended June 30, 1999, as compared to 15% and 17%,
     respectively, of the Registrant's gross lease revenue during the three and
     six-month periods ended June 30, 1998.

     Year 2000

     The Registrant relies upon the financial and operational systems provided
     by the Leasing Company and its affiliates, as well as the systems provided
     by other independent third parties to service the three primary areas of
     its business: investor processing/maintenance; container leasing/asset
     tracking; and accounting finance. The Leasing Company's computer systems
     have undergone modifications in order to render the systems ready for the
     Year 2000. The Leasing Company has completed a detailed inventory of all
     software and hardware systems and has identified all components that need
     to be modified. The Leasing Company has completed all the necessary changes
     and testing in a dedicated Year 2000 environment. The Leasing Company
     anticipates that all compliant code will be live by the end of August 1999.
     The Leasing Company has contacted all of its critical business suppliers
     and has been advised that their systems are Year 2000 compliant. The
     Leasing Company has also confirmed the compliance of its suppliers'
     products through its own extensive testing. Expenses associated with
     addressing Year 2000 issues are being recognized as incurred. Management
     has not yet assessed the Year 2000 compliance expense but does not
     anticipate the costs incurred to date or to be incurred in the future by
     the Leasing Company and its affiliates to be in excess of $500,000. None of
     the costs incurred with respect to Year 2000 compliance will be borne by
     the Registrant. The Leasing Company believes it will be able to resolve any
     major Year 2000 issues. The Leasing Company is aware of the implications of
     a Year 2000 computer system failure and is currently in the process of
     developing its contingency plans. While management believes the possibility
     of a Year 2000 system failure to be remote, if the Leasing

                                       11
<PAGE>   12

     Company's internal systems or those of its critical business suppliers
     fail, the Leasing Company's consolidated financial position, liquidity or
     results of operations may be adversely affected.

     Cautionary Statement

     This Quarterly Report on Form 10-Q contains statements relating to future
     results of the Registrant, including certain projections and business
     trends, that are "forward-looking statements" as defined in the Private
     Securities Litigation Reform Act of 1995. Actual results may differ
     materially from those projected as a result of certain risks and
     uncertainties, including but not limited to changes in: economic
     conditions; trade policies; demand for and market acceptance of leased
     marine cargo containers; competitive utilization and per-diem rental rate
     pressures; as well as other risks and uncertainties, including but not
     limited to those described in the above discussion of the marine container
     leasing business under Item 2., Management's Discussion and Analysis of
     Financial Condition and Results of Operations; and those detailed from time
     to time in the filings of Registrant with the Securities and Exchange
     Commission.


Item 3.  Quantitative and Qualitative Disclosures About Market Risk

         Not applicable.



                                       12
<PAGE>   13

                           PART II - OTHER INFORMATION


Item 1.   Legal Proceedings

          As the Registrant has previously reported, in February 1997, its
          former outside auditors, Arthur Andersen LLP ("Arthur Andersen"),
          resigned as auditors to The Cronos Group (the "Parent Company"), its
          subsidiaries, and all other entities affiliated with the Parent
          Company, including the Registrant. The Parent Company is the indirect
          corporate parent of CCC, the managing general partner of the
          Registrant. CCC does not believe, based upon the information currently
          available to it, that Arthur Andersen's resignation was triggered by
          any concern over the accounting policies and procedures followed by
          the Registrant.

          Arthur Andersen's reports on the financial statements of CCC and the
          Registrant, for years preceding 1996, had not contained an adverse
          opinion or a disclaimer of opinion, nor were any such reports
          qualified or modified as to uncertainty, audit scope, or accounting
          principles.

          During the Registrant's fiscal year ended December 31, 1995, and the
          subsequent interim period preceding Arthur Andersen's resignation,
          there were no disagreements between CCC or the Registrant and Arthur
          Andersen on any matter of accounting principles or practices,
          financial statement disclosure, or auditing scope or procedure.

          In connection with its resignation, Arthur Andersen prepared a report
          pursuant to Section 10A of the Securities Exchange Act of 1934, as
          amended, for filing by the Parent Company with the Securities and
          Exchange Commission ("SEC"). As a result of the Arthur Andersen
          report, the SEC commenced an investigation of the Parent Company on
          February 10, 1997. The purpose of the investigation has been to
          determine whether the Parent Company and persons associated with the
          Parent Company violated the federal securities laws administered by
          the SEC. The Registrant does not believe that the focus of the SEC's
          investigation is upon the Registrant or CCC.

          Current management of the Parent Company has been in discussions with
          the staff of the SEC with a view to settling the investigation. The
          Parent Company is hopeful of reaching a settlement of the
          investigation by the end of 1999.


  Item 3. Defaults Upon Senior Securities

          See Item 5. Other Information.


Item 5.   Other Information

          In 1993, the Parent Company negotiated a credit facility with several
          banks for the use by the Parent Company and its subsidiaries,
          including CCC. At December 31, 1998, approximately $33,110,000 in
          principal indebtedness was outstanding under that credit facility
          (none of which had been borrowed by the Registrant). As a party to
          that credit facility, CCC was jointly and severally liable for the
          repayment of all principal and interest owed under the credit
          facility. On August 2, 1999, all outstanding amounts under the credit
          facility were repaid through the establishment of a new credit
          facility with two financial institutions. CCC is not a party to the
          new loan agreement. The Parent Company has guaranteed up to $10
          million of amounts borrowed under the new credit facility and, as
          partial security for this guarantee, the Parent Company has pledged
          all of the capital stock held by it in Cronos Holding/Investments
          (U.S.), Inc., a Delaware corporation that, in turn, owns all of the
          outstanding capital stock of CCC.

          The Registrant is not a borrower under the new credit facility
          established by the Parent Company, and neither the containers nor the
          other assets of the Registrant have been pledged as collateral under
          the new credit facility.


                                       13
<PAGE>   14

Item 6.   Exhibits and Reports on Form 8-K

(a)   Exhibits
<TABLE>
<CAPTION>

         Exhibit
           No.                             Description                           Method of Filing
         ------                            -----------                           ----------------
<S>       <C>        <C>                                                         <C>
          3(a)       Limited Partnership Agreement of the Registrant, amended    *
                     and restated as of September 12, 1988

          3(b)       Certificate of Limited Partnership of the Registrant        **

          27         Financial Data Schedule                                     Filed with this document
</TABLE>


(b)   Reports on Form 8-K

          No reports on Form 8-K were filed by the Registrant during the quarter
     ended June 30, 1999.



----------------

*    Incorporated by reference to Exhibit "A" to the Prospectus of the
     Registrant dated September 12, 1988, included as part of Registration
     Statement on Form S-1 (No. 33-23321)

**   Incorporated by reference to Exhibit 3.4 to the Registration Statement on
     Form S-1 (No. 33-23321)



                                       14
<PAGE>   15

                                   SIGNATURES



     Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this Report to be signed on its behalf by the
undersigned thereunto duly authorized.




                     IEA INCOME FUND IX, L.P.


                     By  Cronos Capital Corp.
                         The General Partner




                     By  /s/ Dennis J. Tietz
                         --------------------------------------------
                         Dennis J. Tietz
                         President and Director of Cronos Capital Corp. ("CCC")
                         Principal Executive Officer of CCC




Date: August 16, 1999


                                       15
<PAGE>   16

                                  EXHIBIT INDEX
<TABLE>
<CAPTION>

                Exhibit
                  No.                             Description                              Method of Filing
                -------                           -----------                              ----------------
<S>              <C>        <C>                                                            <C>
                 3(a)       Limited Partnership Agreement of the Registrant, amended       *
                            and restated as of September 12, 1988

                 3(b)       Certificate of Limited Partnership of the Registrant           **

                 27         Financial Data Schedule                                        Filed with this document

</TABLE>










------------

*    Incorporated by reference to Exhibit "A" to the Prospectus of the
     Registrant dated September 12, 1988, included as part of Registration
     Statement on Form S-1 (No. 33-23321)

**   Incorporated by reference to Exhibit 3.4 to the Registration Statement on
     Form S-1 (No. 33-23321)