<PAGE>

                                 EXHIBIT 10.9


Line of Credit Agreement
--------------------------------------------------------------------------------

Bank One, Michigan (the "Bank"), whose address is 611 Woodward Avenue, Detroit,
Michigan 48226-3947, has approved the credit facilities listed below
(collectively, the "Credit Facilities," and, individually, as designated below)
to Macatawa Bank Corporation (the "Borrower"), whose address is 51 East Main
Street, Zeeland, MI 49464, subject to the terms and conditions set forth in this
agreement.

1.0  Credit Facilities.

     Facility A.  The Bank has approved a credit facility to the Borrower in the
     principal sum not to exceed $5,000,000.00 in the aggregate at any one time
     outstanding ("Facility A").  Credit under Facility A shall be in the form
     of disbursements evidenced by credits to the Borrower's account and shall
     be repayable as set forth in a Revolving Business Credit Note executed
     concurrently (referred to in this agreement both singularly and together
     with any other promissory notes referenced in this Section 1 as the
     "Notes").  The proceeds of Facility A shall be used for the following
     purpose:  Investment in bank subsidiary Macatawa Bank, investment in its
     Trust Services subsidiary or working capital.  Facility A shall expire
     September 26, 2001, unless earlier withdrawn.

2.0  Conditions Precedent.

     2.1  Conditions Precedent to Initial Extension of Credit.  Before the first
          extension of credit under this agreement, whether by disbursement of a
          loan, issuance of a letter of credit, the funding of a Lease or
          otherwise, the Borrower shall deliver to the Bank, in form and
          substance satisfactory to the Bank:

          A.   Loan Documents. The Notes, and if applicable, the Leases, the
               letter of credit applications, the security agreement, financing
               statements, mortgage, guaranties, subordination agreements and
               any other loan documents which the Bank may reasonably require to
               give effect to the transactions described by this agreement;

          B.   Evidence of Due Organization and Good Standing. Evidence
               satisfactory to the Bank of the due organization and good
               standing of the Borrower and every other business entity that is
               a party to this agreement or any other loan document required by
               this agreement;

          C.   Evidence of Authority to Enter into Loan Documents. Evidence
               satisfactory to the Bank that (i) each party to this agreement
               and any other loan document required by this agreement is
               authorized to enter into the transactions described by this
               agreement and the other loan documents, and (ii) the person
               signing on behalf of each party is authorized to do so; and
<PAGE>

     2.2  Conditions Precedent to Each Extension of Credit. Before any extension
          of credit under this agreement, whether by disbursement of a loan,
          issuance of a letter of credit, the funding of a Lease or otherwise,
          the following conditions shall have been satisfied:

          A.   Representations. The Representations contained in this agreement
               shall be true on and as of the date of the extension of credit;

          B.   No Event of Default. No event of default shall have occurred and
               be continuing or would result from the extension of credit;

          C.   Additional Approvals, Opinions, and Documents. The Bank shall
               have received such other approvals, opinions and documents as it
               may reasonably request.

3.0  Borrowing Base/Annual Pay Down.

     3.1  Borrowing Base. Notwithstanding any other provision of this agreement,
          the aggregate principal amount outstanding at any one time under
          Facility A, shall not exceed the lesser of the Borrowing Base or
          $5,000,000.00. Borrowing Base means:

          A.   50% of the tangible book value of the common stock of Macatawa
               Bank.

4.0  Fees and Expenses.

     4.1  Fees.  Upon execution of this agreement, or as set forth below, the
          Borrower shall pay the Bank the following fees, all of which the
          Borrower acknowledges have been earned by the Bank:  $4,000.00
          ($2,000.00) prepayment paid by borrower).

     4.2  Out-of-Pocket Expenses. The Borrower shall reimburse the Bank for its
          out-of-pocket expenses, and reasonable attorney's fees (including the
          fees of in-house counsel) allocated to the Credit Facilities.

5.0  Security

     5.1  Payment of the borrowings and all other obligations under the Credit
          Facilities shall be secured by a first security interest and/or real
          estate mortgage, as the case may be, covering the following property
          and all its additions, substitutions, increments, proceeds and
          products, whether now owned or later acquired ("Collateral"):

          A.   Common Stock. Common stock of Macatawa Bank representing
               ownership, voting interest and having $10,000,000.00 book value.

                             Exhibit 10.9 - Page 2
<PAGE>

          Should the borrowers subsidiary bank, Macatawa Bank, incur a ratio of
          Non-Performing Assets to Total Loans Plus OREO exceeding 1.75%, a net
          loss for any fiscal quarter ending or any financial default of the
          credit agreement, the borrower agrees to pledge at the request of Bank
          One Michigan, Common Shares of Macatawa Bank Stock necessary to
          represent 51% voting and ownership interest.

     5.2  No forbearance or extension of time granted any subsequent owner of
          the Collateral shall release the Borrower from liability.

     5.3  Additional Collateral/Setoff. To further secure payment of the
          borrowings and all other obligations under the Credit Facilities and
          all of the Borrower's other liabilities to the Bank, the Borrower
          grants to the Bank a continuing security interest in: (i) all
          securities and other property of the Borrower in the custody,
          possession or control of the Bank (other than property held by the
          Bank solely in a fiduciary capacity) and (ii) all balances of deposit
          accounts of the Borrower with the Bank. The Bank shall have the right
          at any time to apply its own debt or liability to the Borrower, or to
          any other party liable for payment of the obligations under the Credit
          Facilities, in whole or partial payment of such obligations or other
          present or future liabilities, without any requirement of mutual
          maturity.

     5.4  Cross Lien. Any of the Borrower's other property in which the Bank has
          a security interest to secure payment of any other debt, whether
          absolute, contingent, direct or indirect, including the Borrower's
          guaranties of the debts of others, shall also secure payment of and be
          part of the Collateral for the Credit Facilities.

6.0  This section intentionally left blank.

7.0  This section intentionally left blank.

8.0  Affirmative Covenants. So long as any debt or obligation remains
     outstanding under the Credit Facilities, the Borrower, and each of its
     subsidiaries, if any, shall:

     8.1  Insurance.  Maintain insurance with financially sound and reputable
          insurers covering its properties and business against those casualties
          and contingencies and in the types and amounts as shall be in
          accordance with sound business and industry practices.

     8.2  Existence. Maintain its existence and business operations as presently
          in effect in accordance with all applicable laws and regulations, pay
          its debts and obligations when due under normal terms, and pay on or
          before their due date, all taxes, assessments, fees and other
          governmental monetary obligations, except as they may be contested in
          good faith if they have been properly reflected on its books and, at
          the Bank's request, adequate funds or security has been pledged to
          insure payment.

                             Exhibit 10.9 - Page 3
<PAGE>

     8.3  Financial Records.  Maintain proper books and records of account, in
          accordance with generally accepted accounting principles where
          applicable, and consistent with financial statements previously
          submitted to the Bank.  The Bank retains the right to inspect the
          Collateral and business records related to it at such times and at
          such intervals as the Bank may reasonably require.

     8.4  Notice. Give prompt notice to the Bank of the occurrence of (i) any
          Event of Default, and (ii) any other development, financial or
          otherwise, which would affect the Borrower's business, properties or
          affairs in a materially adverse manner.

     8.5  Financial Reports. Furnish to the Bank whatever information, books,
          and records the Bank may reasonably request, including at a minimum:
          (If the Borrower has subsidiaries, all financial statements required
          will be provided on a consolidated and on a separate basis.)

          A.   Within 45 days after each interim quarterly period, a call report
               of bank subsidiaries.

          B.   Within 45 days after each interim quarterly period, a 10Q
               financial statement including: a balance sheet as of the end of
               that period, and statements of income, retained earning, from the
               beginning of that fiscal year to the end of that period,
               certified as correct by one of its management authorized agents.

          C.   Within 120 days after, and as of the end of, each of its fiscal
               years, a detailed audit including a balance sheet and statements
               of income, cash flows, and retained earnings, certified by an
               independent certified public accountant of recognized standing.

          D.   Within 45 days after and as of the end of each fiscal quarter, a
               calculation of the financial covenants for this credit facility
               certified as correct and accurate by one of its authorized
               agents.

9.0  Negative Covenants.

     9.1  Definitions. As used in this agreement, the following terms shall have
          the following respective meanings:

          A.   "Debt Service" means for any period, principal and interest
               payments either paid or due during that period on all debt of the
               Borrower.

          B.   "EBITDA" means for any period, net income plus to the extent
               deducted in determining net income, interest expense (including
               but not limited to

                             Exhibit 10.9 - Page 4
<PAGE>

               imputed interest on capital leases), tax expense, depreciation,
               and amortization.

          C.   "Subordinated Debt" means debt subordinated to the Bank in manner
               and by agreement satisfactory to the Bank.

          D.   "Tangible Net Worth" means total assets less intangible assets,
               total liabilities, and all sums owing from stockholders, members,
               or partners, as the case may be, and from officers, managers, and
               directors. Intangible assets include goodwill, patents,
               copyrights, mailing lists, catalogs, trademarks, bond discount
               and underwriting expenses, organization expenses, and all other
               intangibles.

     9.2  Unless otherwise noted, the financial requirements set forth in this
          section shall be computed in accordance with generally accepted
          accounting principals applied on a basis consistent with financial
          statements previously submitted by the Borrower to the Bank.

     9.3  Without the written consent of the Bank, so long as any debt or
          obligation remains outstanding under the Credit Facilities, the
          Borrower shall not: (where appropriate, covenants apply on a
          consolidated basis).

          A.   Debt. Incur, or permit to remain outstanding, debt for borrowed
               money or installment obligations, except debt reflected in the
               latest financial statement of the Borrower furnished to the Bank
               prior to execution of this agreement and not to be paid with
               proceeds of borrowings or leases under the Credit Facilities. For
               purposes of this covenant, the sale of any accounts receivable
               shall be deemed the incurring of debt for borrowed money.

          D.   Guaranties. Guarantee or otherwise become or remain secondarily
               liable on the undertaking of another, except for endorsement of
               drafts for deposit and collection in the ordinary course of
               business. This covenant does not limit the normal activity of
               Borrower's subsidiary bank, Macatawa Bank.

          E.   Liens. Create or permit to exist any lien on any of its property,
               real or personal, except: existing liens known to the Bank; liens
               to the Bank; liens incurred in the ordinary course of business
               securing current nondelinquent liabilities for taxes, worker's
               compensation, unemployment insurance, social security and pension
               liabilities; and liens for taxes being contested in good faith.
               This covenant does not limit the normal activity of Borrowers
               subsidiary bank, Macatawa Bank.

          F.   Advances and Investments. Purchase or acquire any securities of,
               or make any loans or advances to, or investments in, any person,
               firm or corporation, except as described as the purpose of
               Facility A plus

                             Exhibit 10.9 - Page 5
<PAGE>

               obligations of the United States Government, open market
               commercial paper rated one of the top two ratings by a rating
               agency of recognized standing, or certificates of deposit in
               insured financial institutions. This covenant does not limit the
               normal activity of Borrowers subsidiary bank, Macatawa Bank.

          G.   Use of Proceeds. Use, or permit any proceeds of the Credit
               Facilities to be used, directly or indirectly, for the purpose of
               "purchasing or carrying any margin stock" within the meaning of
               Federal Reserve Board Regulation U. At the Bank's request, the
               Borrower shall furnish to the Bank a completed Federal Reserve
               Board Form U-1.

          H.   Non-performing Loan Ratio. Permit the ratio of Nonperforming
               Assets to Total Loans and Other Real Estate and Repossessed
               Assets Owned to exceed 2.25%.

          I.   Loan Loss Reserves. Permit the ratio of Loan Loss reserves to
               Non-performing assets to be less than 100%.

          J.   Tangible Net North to Total Assets. Permit its ratio of Tangible
               Net Worth to Total Assets to be less than 7.0%.

          K.   Leverage Ratio. Permit the ratio of its Total Debt to its
               Tangible net Worth to exceed .50 to 1.00. (For the purposes of
               this covenant, Total Debt does not include Borrowed Money of its
               Bank Subsidiary.

          L.   Well Capitalized. The Borrower will remain "Well Capitalized" as
               defined by the applicable regulatory agencies.

          M.   Leases. Contract for or assume in any manner lease obligations if
               the aggregate of all payments shall exceed $100,000 in any one
               fiscal year, excluding, however, obligations under prior year
               Leases.

10.0 Representations by Borrower.  Each Borrower represents that:  (a) the
     execution and delivery of this agreement, the Notes, and the Leases and the
     performance of the obligations they impose do not violate any law, conflict
     with any agreement by which the Borrower is bound, or require the consent
     or approval of any governmental authority or other third party for which
     consent or approval has not been granted; (b) this agreement, the Notes,
     and the Leases are valid and binding agreements, enforceable in accordance
     with their terms; and (c) all balance sheets, profit and loss statements,
     and other financial statements furnished to the Bank are accurate and
     fairly reflect the financial condition of the organizations and persons to
     which they apply on their effective dates, including contingent liabilities
     of every type, which financial condition has not changed materially and
     adversely since those dates.  Each Borrower, if other than a natural
     person, further represents that:  (a) it is duly organized, existing and in
     good standing under the laws of the jurisdiction under which it was
     organized; and (b) the execution and delivery of this

                             Exhibit 10.9 - Page 6
<PAGE>

     agreement, the Notes, and the Leases and the performance of the obligations
     they impose (i) are within its power; (ii) have been duly authorized by all
     necessary action of its governing body; and (iii) do not contravene the
     terms of its articles of incorporation or organization, its bylaws, or any
     partnership, operating or other agreement governing its affairs.

11.0 Default/Acceleration.

     11.1 Events of Default/Acceleration. If any of the following events occurs,
          the Credit Facilities shall terminate and all borrowings and other
          obligations under them shall be due immediately, without notice, at
          the Bank's option whether or not the Bank has made demand.

          A.   The Borrower or any guarantor of any of the Credit Facilities,
               the Notes or the Leases ("Guarantor") fails to pay when due any
               amount payable under the Credit Facilities or under any agreement
               or instrument evidencing debt to any creditor;

          B.   The Borrower or any Guarantor (a) fails to observe or perform any
               other term of this agreement, the Notes, or the Leases; (b) makes
               any materially incorrect or misleading representation, warranty,
               or certificate to the Bank; (c) makes any materially incorrect or
               misleading representation in any financial statement or other
               information delivered to the Bank; or (d) defaults under the
               terms of any agreement or instrument relating to any debt for
               borrowed money (other than borrowings under the Credit
               Facilities) such that the creditor declares the debt due before
               its maturity;

          C.   There is a default under the terms of any loan agreement,
               mortgage, security agreement or any other document executed as
               part of the Credit Facilities, or any guaranty of the obligations
               under the Credit Facilities becomes unenforceable in whole or in
               part, or any Guarantor fails to promptly perform under its
               guaranty;

          D.   A "reportable event" (as defined in the Employee Retirement
               Income Security Act of 1974 as amended ) occurs that would permit
               the Pension Benefit Guaranty Corporation to terminate any
               employee benefit plan of the Borrower or any affiliate of the
               Borrower;

          E.   The Borrower or any Guarantor becomes insolvent or unable to pay
               its debts as they become due;

          F.   The Borrower or any Guarantor (a) makes an assignment for the
               benefit of creditors; (b) consents to the appointment of a
               custodian, receiver or trustee for it or for a substantial part
               of its assets; or (c) commences any proceeding under any
               bankruptcy, reorganization, liquidation or similar laws of any
               jurisdiction;

                             Exhibit 10.9 - Page 7
<PAGE>

          G.   A custodian, receiver or trustee is appointed for the Borrower or
               any Guarantor or for a substantial part of its assets without its
               consent and is not removed within 60 days after such appointment;

          H.   Proceedings are commenced against the Borrower or any Guarantor
               under any bankruptcy, reorganization, liquidation, or similar
               laws of any jurisdiction, and such proceedings remain undismissed
               for 60 days after commencement; or the Borrower or Guarantor
               consents to the commencement of such proceedings;

          I.   Any judgment is entered against the Borrower or any Guarantor or
               any attachment, levy or garnishment is issued against any
               property of the Borrower or any Guarantor;

          J.   The Borrower or any Guarantor, without the Bank's written consent
               (a) is dissolved, (b) merges or consolidates with any third
               party, (c) leases, sells or otherwise conveys a material part of
               its assets of business outside the ordinary course of business,
               (d) leases, purchases, or otherwise acquires a material part of
               the assets of any other corporation or business entity, except in
               the ordinary course of business, or (e) agrees to do any of the
               foregoing, (notwithstanding the foregoing, any subsidiary may
               merge or consolidate with any other subsidiary, or with the
               Borrower, so long as the Borrower is the survivor);

          L.   The loan-to-book value ratio of any pledged securities at any
               time exceeds 50% , and such excess continues for five (5) days
               after notice from the Bank to the Borrower;

          M.   There is a substantial change in the existing or prospective
               financial condition of the Borrower or any Guarantor which the
               Bank in good faith determines to be materially adverse.

     11.2 Remedies. If the borrowings and all other obligations under the Credit
          Facilities are not paid at maturity, whether by acceleration or
          otherwise, the Bank shall have all of the rights and remedies provided
          by any law or agreement. Any requirement of reasonable notice shall be
          met if the Bank sends the notice to the Borrower at least seven (7)
          days prior to the date of sale, disposition or other event giving rise
          to the required notice. The Bank is authorized to cause all or any
          part of the Collateral to be transferred to or registered in its name
          or in the name of any other person, firm, or corporation, with or
          without designation of the capacity of such nominee. The Borrower
          shall be liable for any deficiency remaining after disposition of any
          Collateral. The Borrower is liable to the Bank for all reasonable
          costs and expenses of every kind incurred in the making or collection
          of the Credit Facilities, including, without limitation, reasonable
          attorney's fees and court costs (whether attributable to the Bank's
          in-house or

                             Exhibit 10.9 - Page 8
<PAGE>

          outside counsel). These costs and expenses shall include, without
          limitation, any costs or expenses incurred by the Bank in any
          bankruptcy, reorganization, insolvency or other similar proceeding.

12.0 Miscellaneous.

     12.1 Notice from one party to another relating to this agreement shall be
          deemed effective if made in writing (including telecommunications) and
          delivered to the recipient's address, telex number or fax number set
          forth under its name below by any of the following means: (a) hand
          delivery, (b) registered or certified mail, postage prepaid, with
          return receipt requested, (c) first class or express mail, postage
          prepaid, (d) Federal Express or like overnight courier service or (e)
          fax, telex or other wire transmission with request for assurance of
          receipt in a manner typical with respect to communication of that
          type. Notice made in accordance with this section shall be deemed
          delivered upon receipt if delivered by hand or wire transmission, 3
          business days after mailing if mailed by first class, registered or
          certified mail, or one business day after mailing or deposit with an
          overnight courier service if delivered by express mail or overnight
          courier.

     12.2 No delay on the part of the Bank in the exercise of any right or
          remedy shall operate as a waiver. No single or partial exercise by the
          Bank of any right or remedy shall preclude any other future exercise
          of it or the exercise of any other right or remedy. No waiver or
          indulgence by the Bank of any default shall be effective unless in
          writing and signed by the Bank, nor shall a waiver on one occasion be
          construed as a bar to or waiver of that right on any future occasion.

     12.3 This agreement, the Notes, the Leases and any related loan documents
          embody the entire agreement and understanding between the Borrower and
          the Bank and supersede all prior agreements and understandings
          relating to their subject matter. If any one or more of the
          obligations of the Borrower under this agreement, the Notes or the
          Leases shall be invalid, illegal or unenforceable in any jurisdiction,
          the validity, legality and enforceability of the remaining obligations
          of the Borrower shall not in any way be affected or impaired, and such
          invalidity, illegality or unenforceability in on jurisdiction shall
          not affect the validity, legality or enforceability of the obligations
          of the Borrower under this agreement, the Notes or the Leases in any
          other jurisdiction.

     12.4 The Borrower, if more than one, shall be jointly and severally liable.

     12.5 This agreement is delivered in the State of Michigan and governed by
          Michigan law. This agreement is binding on the Borrower and its
          successors, and shall inure to the benefit of the Bank, its successors
          and assigns.

     12.6 Section headings are for convenience of reference only and shall not
          affect the interpretation of this agreement.

                             Exhibit 10.9 - Page 9
<PAGE>

     13.0 Information Sharing. The Bank may provide, without any limitation
          whatsoever, any information or knowledge the Bank may have about the
          undersigned or any matter relating to this agreement and related
          documents to BANK ONE CORPORATION, or any of its subsidiaries or
          affiliates or their successors, or to any one or more purchasers or
          potential purchasers of this agreement or any related documents, and
          the undersigned excluding confidential information, waives any right
          to privacy the undersigned may have with respect to such matters. The
          Borrower agrees that the Bank may at any time sell, assign or transfer
          one or more interests or participations in all or any part of its
          rights or obligations in this agreement to one or more purchasers
          whether or not related to the Bank.

     14.0 Waiver of Jury Trial. The Bank and the Borrower knowingly and
          voluntarily waive any right either of them have to a trial by jury in
          any proceeding (whether sounding in contract or tort) which is in any
          way connected with this or any related agreement, or the relationship
          established under them. This provision may only be modified in a
          written instrument executed by the Bank and the Borrower.

Executed by the parties on: September 26, 2000

Bank One, Michigan                      Borrower Macatawa Bank Corporation


    /s/ Roger A. Bick                         /s/ Benj A. Smith III
---------------------------------       ---------------------------------------
Roger A. Bick, Vice President           Benj A. Smith III  Its:  Chairman

Address for Notices                     Address for Notices

611 Woodward Ave. MI1-8077              248 Waverly Rd.
Detroit, Michigan 48226                 Suite 2C-Adm.
                                        Holland, Michigan 49423

Fax/Telex No. (313) 225-1141            Fax/Telex No. (616) 494-7644

                            Exhibit 10.9 - Page 10