<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 SEPTEMBER 30, 1996

                                       OR

[ ]   TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES 
      EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD 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 SEPTEMBER 30, 1996

                                TABLE OF CONTENTS


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

Item 1.   Financial Statements

          Balance Sheets - September 30, 1996 (unaudited) and December 31, 1995                                       4

          Statements of Operations for the three and nine months ended September 30, 1996 and 1995 (unaudited)        5

          Statements of Cash Flows for the nine months ended September 30, 1996 and 1995 (unaudited)                  6

          Notes to Financial Statements (unaudited)                                                                   7

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


PART II - OTHER INFORMATION

Item 6.   Exhibits and Reports on Form 8-K                                                                           12
</TABLE>


                                       2
<PAGE>   3

                         PART I - FINANCIAL INFORMATION


Item 1.   Financial Statements

          Presented herein are the Registrant's balance sheets as of September
          30, 1996 and December 31, 1995, statements of operations for the three
          and nine months ended September 30, 1996 and 1995, and statements of
          cash flows for the nine months ended September 30, 1996 and 1995.






                                       3
<PAGE>   4
                            IEA INCOME FUND IX, L.P.

                                 BALANCE SHEETS

                                   (UNAUDITED)


<TABLE>
<CAPTION>
                                                                              September 30,      December 31,
                                                                                  1996              1995
                                                                              -------------      ------------  
<S>                                                                           <C>                <C>
                   Assets
Current assets:
     Cash, includes $227,432 at September 30, 1996 and $234,018
         at December 31, 1995 in interest-bearing accounts                    $   227,816         $   234,242
     Short-term investments                                                       827,499             875,436
     Net lease receivables due from Leasing Company
         (notes 1 and 2)                                                          533,907             589,878
                                                                              -----------         -----------

              Total current assets                                              1,589,222           1,699,556
                                                                              -----------         -----------

Container rental equipment, at cost                                            16,658,916          17,104,812
     Less accumulated depreciation                                              6,663,538           6,110,733
                                                                              -----------         -----------
         Net container rental equipment                                         9,995,378          10,994,079
                                                                              -----------         -----------

                                                                              $11,584,600         $12,693,635
                                                                              ===========         ===========
     Liabilities and Partners' Capital

Current liabilities:
     Due to general partner and its affiliates (notes 1 and 3)                $      4,743        $    17,981
                                                                              -----------         -----------
Partners' capital (deficit):
     General partner                                                              (13,209)                166
     Limited partners                                                          11,593,066          12,675,488
                                                                              -----------         -----------

              Total partners' capital                                          11,579,857          12,675,654
                                                                              -----------         -----------
                                                                              $11,584,600         $12,693,635
                                                                              ===========         ===========
</TABLE>

        The accompanying notes are an integral part of these statements.


                                       4
<PAGE>   5
                            IEA INCOME FUND IX, L.P.

                            STATEMENTS OF OPERATIONS

                                   (UNAUDITED)


<TABLE>
<CAPTION>
                                                           Three Months Ended                   Nine Months Ended
                                                     ------------------------------     ------------------------------
                                                     September 30,    September 30,     September 30,    September 30,
                                                         1996             1995              1996             1995
                                                     -------------    -------------     -------------    -------------
<S>                                                  <C>              <C>               <C>              <C>
Net lease revenue (notes 1 and 4)                      $515,180         $610,105         $1,523,822       $1,964,643
Other operating expenses:                                                            
   Depreciation                                         243,419          358,163            738,145          862,871
   Other general and administrative expenses             10,767            4,597             28,258           34,836
                                                       --------         --------         ----------       ----------
                                                        254,186          362,760            766,403          897,707
                                                       --------         --------         ----------       ----------
     Earnings from operations                           260,994          247,345            757,419        1,066,936
Other income:                                                                        
   Interest income                                       13,992           15,650             41,654           48,909
   Net gain on disposal of equipment                     10,453           20,324                589           32,578
                                                       --------         --------         ----------       ----------
                                                         24,445           35,974             42,243           81,487
                                                       --------         --------         ----------       ----------
     Net earnings                                      $285,439         $283,319         $  799,662       $1,148,423
                                                       ========         ========         ==========       ==========
Allocation of net earnings:                                                          
   General partner                                     $ 30,777         $ 41,187         $   76,248       $  111,401
   Limited partners                                     254,662          242,132            723,414        1,037,022
                                                       --------         --------         ----------       ----------
                                                       $285,439         $283,319         $  799,662       $1,148,423
                                                       ========         ========         ----------       ==========
Limited partners' per unit share of net earnings       $   7.49         $   7.13         $    21.28       $    30.51
                                                       ========         ========         ==========       ==========
</TABLE>

        The accompanying notes are an integral part of these statements.



                                       5
<PAGE>   6

                            IEA INCOME FUND IX, L.P.

                            STATEMENTS OF CASH FLOWS

                                   (UNAUDITED)

<TABLE>
<CAPTION>
                                                                  Nine Months Ended
                                                            --------------------------------
                                                            September 30,      September 30,
                                                                1996               1995
                                                            -------------      ------------- 
<S>                                                         <C>                <C>
Net cash provided by operating activities                    $ 1,586,423        $ 2,217,158

Cash flows provided by (used in) investing activities:
   Proceeds from sale of container rental equipment              267,911             82,315
   Acquisition fees paid to general partner                      (13,238)           (16,404)
                                                             -----------        -----------

         Net cash provided by investing activities               254,673             65,911
                                                             -----------        -----------

Cash flows used in financing activities:
   Distribution to partners                                   (1,895,459)        (2,098,535)
                                                             -----------        -----------

Net increase (decrease) in cash and cash equivalents             (54,363)           184,534

Cash and cash equivalents at January 1                         1,109,678          1,025,586
                                                             -----------        -----------

Cash and cash equivalents at September 30                    $ 1,055,315        $ 1,210,120
                                                             ===========        ===========
</TABLE>


        The accompanying notes are an integral part of these 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 and
          controls the business of the Partnership.

      (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.

      (c) Basis of Accounting

          The Partnership utilizes the accrual method of accounting. Revenue is
          recognized when earned.

          The Partnership has determined that for accounting purposes the
          Leasing Agent Agreement is a lease, and the receivables, payables,
          gross revenues and operating expenses attributable to the containers
          managed by the Leasing Company are, for accounting purposes, those of
          the Leasing Company and not of the Partnership. Consequently, the
          Partnership's balance sheets and statements of operations display the
          payments to be received by the Partnership from the Leasing Company as
          the Partnership's receivables and revenues.


                                                                     (Continued)

                                       7
<PAGE>   8

                            IEA INCOME FUND IX, L.P.

                     NOTES TO UNAUDITED FINANCIAL STATEMENTS


      (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.

          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, the
      Leasing Company, 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 September 30, 1996 and December 31, 1995 were as follows:

<TABLE>
<CAPTION>
                                                                  September 30,    December 31,
                                                                      1996             1995
                                                                  -------------    ------------
<S>                                                               <C>              <C>
         Lease receivables, net of doubtful accounts
              of $206,408 at September 30, 1996 and $138,066
              at December 31, 1995                                  $770,075         $944,386
         Less:
         Direct operating payables and accrued expenses               88,386          148,076
         Damage protection reserve                                    77,077          108,033
         Base management fees                                         57,311           82,254
         Reimbursed administrative expenses                           13,394           16,145
                                                                    --------         --------
                                                                    $533,907         $589,878
                                                                    ========         ========
</TABLE>

(3)   Due to General Partner

      The amounts due to CCC at September 30, 1996 and December 31, 1995 consist
      of acquisition fees.


                                                                     (Continued)


                                       8
<PAGE>   9
                            IEA INCOME FUND IX, L.P.

                     NOTES TO UNAUDITED FINANCIAL STATEMENTS


(4)   Net Lease Revenue

      Net lease revenue is determined by deducting direct operating expenses,
      management fees and reimbursed administrative expenses to CCC, and the
      Leasing Company, 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 nine-month periods ended
      September 30, 1996 and 1995, was as follows:

<TABLE>
<CAPTION>
                                                         Three Months Ended                  Nine Months Ended
                                                   ------------------------------     ------------------------------
                                                   September 30,    September 30,     September 30,    September 30,
                                                       1996             1995              1996             1995
                                                   -------------    -------------     -------------    -------------    
<S>                                                <C>              <C>               <C>             <C>
           Rental revenue                            $747,360         $936,980          $2,377,997      $2,804,678
           Rental equipment operating expenses        137,764          211,916             571,234         502,091
           Base management fees                        52,655           59,029             156,488         186,386
           Reimbursed administrative expenses          41,761           55,930             126,453         151,558
                                                     --------         --------          ----------      ----------
                                                     $515,180         $610,105          $1,523,822      $1,964,643
                                                     ========         ========          ==========      ==========
</TABLE>



                                       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 September 30, 1996 and
      December 31, 1995.

      During the first nine months of 1996, the Registrant disposed of 121
      containers as part of its ongoing operations, contributing to the change
      in the Registrant's financial condition. At September 30, 1996, 93% of the
      original equipment remained in the Registrant's fleet, as compared to 96%
      at December 31, 1995, comprised as follows:

<TABLE>
<CAPTION>
                                                                  40-Foot
                                           20-Foot    40-Foot    High-Cube
<S>                                        <C>        <C>        <C>
         Containers on lease:
              Term leases                     151         55           83
              Master lease                  1,445        522        1,250
                                            -----        ---        -----
                  Subtotal                  1,596        577        1,333
         Containers off lease                 584        171          189
                                            -----        ---        -----
              Total container fleet         2,180        748        1,522
                                            =====        ===        =====
</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                        147        6%       51       6%        131        8%
                                                  -----     ----       ---     ---       -----      ---
         Remaining fleet at September 30, 1996    2,180       94%      748      94%      1,522       92%
                                                  =====     ====       ===     ===       =====      ===
</TABLE>

      Net lease receivables at September 30, 1996, declined when compared to
      December 31, 1995. Contributing to this decline were favorable collections
      of the Registrant's lease receivables and a decline in the fleet's
      operating performance. A reduction in the Registrant's fleet size, as well
      as the fleet's related operating performance, also contributed to a
      decline in direct operating payables, damage protection reserve,
      reimbursed administrative expenses payable and base management fees
      payable.

      During the third quarter of 1996, distributions from operations and sales
      proceeds amounted to $578,735, reflecting distributions to the general and
      limited partners for the second quarter of 1996. This represents a decline
      from the $613,635 distributed during the second quarter of 1996,
      reflecting increased distributions of sales proceeds for the second
      quarter of 1996. Additional container disposals, combined with current
      leasing market conditions, may contribute to lower operating results and,
      consequently, lower distributions from operations to its partners in
      subsequent periods. However, sales proceeds distributed to its partners
      may fluctuate in subsequent periods, reflecting the level of container
      disposals.

      The statements contained in the following discussion are based on current
      expectations. These statements are forward looking and actual results may
      differ materially. Indicative of the cyclical nature of the container
      leasing business, containerized trade slowed in the last quarter of 1995,
      and excess inventories began to develop. This slowdown has resulted in
      reduced equipment utilization and lower per-diem rental rates in the
      container leasing industry during the first nine months of 1996.
      Accordingly, the Registrant's utilization rate has declined from an
      average of 87% at December 31, 1995 to 80% at September 30, 1996. During
      the first nine months of 1996, the Leasing Company implemented various
      marketing strategies, including but not limited to, offering incentives to
      shipping companies and repositioning containers to high demand locations
      in order to counter the market conditions. Ancillary revenues have fallen,
      and free-day incentives offered to the shipping lines have increased. In
      addition, rental equipment operating expenses of the Registrant have
      increased due to higher storage and handling costs associated with the
      off-hire fleet, 

                                       10
<PAGE>   11


      and increased repositioning costs. These leasing market conditions are
      expected to adversely impact the Registrant's results from operations
      through the remainder of 1996 and into 1997.


2)    Material changes in the results of operations between the three and
      nine-month periods ended September 30, 1996 and the three and nine-month
      periods ended September 30, 1995.

      Net lease revenue for the three and nine-month periods ended September 30,
      1996 was $515,180, and $1,523,822, respectively, a decline of 16% and 22%
      from the same three and nine-month periods in the prior year,
      respectively. Gross rental revenue (a component of net lease revenue) for
      the three and nine-month periods ended September 30, 1996 was $747,360 and
      $2,377,997, respectively, reflecting a decline of 20% and 15% from the
      same three and nine-month periods in 1995, respectively. During 1996,
      gross rental revenue was primarily impacted by the Registrant's lower
      per-diem rental rates and utilization levels. Average per-diem rental
      rates decreased approximately 6% and 3%, when compared to the same three
      and nine-month periods in the prior year, respectively, as they became
      subject to the downward pressures of an increasingly soft container
      leasing market. The Registrant's average fleet size and utilization rates
      for the three and nine-month periods ended September 30, 1996 and
      September 30, 1995 were as follows:

<TABLE>
<CAPTION>
                                                           Three Months Ended                 Nine Months Ended
                                                     ------------------------------     ------------------------------  
                                                     September 30,    September 30,     September 30,    September 30,
                                                        1996             1995              1996             1995
                                                     -------------    -------------     -------------    -------------
<S>                                                  <C>              <C>               <C>              <C>
         Average Fleet Size (measured in
             twenty-foot equivalent units (TEU))        6,726             6,947            6,813            6,975
         Average Utilization                               82%               89%              82%              90%
</TABLE>


      Rental equipment operating expenses were 18% and 23% of the Registrant's
      gross lease revenue for the three-month periods ended September 30, 1996
      and 1995, respectively. This decline was primarily attributable to a
      reduction in the provision for doubtful accounts. However, rental
      equipment operating expenses were 24% and 18% of the Registrant's gross
      lease revenue for the nine-month periods ended September 30, 1996 and
      1995, respectively. This increase was largely attributable to a decline in
      gross lease revenue resulting from lower utilization rates, lower per-diem
      rates, a downward trend in ancillary revenue, and an increase in free-day
      incentives offered to shipping companies. Costs associated with lower
      utilization levels, including storage, handling, and repositioning, also
      contributed to the increase in rental equipment operating expenses, as a
      percentage of gross lease revenue. A reduction in the Registrant's average
      fleet size and its related operating performance contributed to the
      decline in base management fees, when compared to the same periods in the
      prior year.



                                       11
<PAGE>   12

                           PART II - OTHER INFORMATION


Item 6.   Exhibits and Reports on Form 8-K

(a)   Exhibits

<TABLE>
<CAPTION>

      Exhibit
        No.                        Description                                                Method of Filing
      -------                      -----------                                                ----------------
<S>                 <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 September 30, 1996



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

*      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)



                                       12
<PAGE>   13
                                   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/ JOHN KALLAS
                                       ----------------------------------------
                                       John Kallas
                                       Vice President, Treasurer
                                       Principal Financial & Accounting Officer



Date:  November 11, 1996






                                       13
<PAGE>   14

                                  EXHIBIT INDEX


<TABLE>
<CAPTION>

Exhibit
  No.                                   Description                                    Method of Filing
-------                                 -----------                                    ----------------
<S>           <C>                                                                      <C>
 (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)