<PAGE>   1
                                                                     Exhibit 3.9

                          CERTIFICATE OF INCORPORATION
                         OF WERNER FUNDING CORPORATION

        ARTICLE I: NAME. The name of the Corporation is Werner Funding
Corporation.

        ARTICLE II: REGISTERED OFFICE. The address of the Corporation's
registered office in the State of Delaware is 1105 North Market Street, Suite
1300, Wilmington, New Castle County, Delaware, 19801. The name of the
Corporation's registered agent at such address is Delaware Corporate Management,
Inc.

        ARTICLE III: PURPOSE.

        Section 1. The nature of the business to be conducted by the
Corporation is to engage solely in the following activities:

        (a) to do one or more of the following: (i) own, hold, sell, assign,
pledge, lease, finance, trade, exchange and otherwise deal in the trade
receivables and rights related thereto of Werner Co. (the "Trade Receivables");
(ii) hold cash and cash equivalents in deposit accounts from time to time
derived from transactions relating to the Trade Receivables; (iii) acquire other
assets arising out of or in any way related to the Trade Receivables or
transactions involving the foregoing; and (iv) acquire all income, payments
(including insurance payments) and proceeds of the foregoing;

        (b) to exercise all of its rights, powers, duties and obligations under
the Receivables Purchase Agreement, among the Corporation, Werner Co., Market
Street Funding Corporation and PNC Bank, National Association, as amended from
time to time (the "Receivables Purchase Agreement"); and the Purchase and Sale
Agreement, between the Corporation and Werner Co., as amended from time to time
(the "Purchase and Sale Agreement");

        (c) to pay any and all costs and expenses incurred in connection with
the foregoing, including but not limited to, legal, accounting and servicing
fees and expenses, principal and interest on loans made to the Corporation, the
cost of any financing, including fees incurred in connection with the placement
thereof, taxes and insurance;

        (d) to exercise all powers enumerated in the Delaware General
Corporation Law that are incident to and necessary or convenient to the conduct
of the business described above; and

        (e) to engage in any lawful acts or activities that are incidental to
and necessary or convenient for the accomplishment of such purpose, including
without limitation, entering into agreements to service the Trade Receivables.

        Section 2. The Corporation: (i) is organized solely for the purposes set
forth in Section 1 of this Article III, and will not engage in any business
unrelated to the purposes set 
<PAGE>   2
forth in Section 1 of this Article III; (ii) will not have any material assets
other than the Trade Receivables; (iii) shall, at all times have at least one
director (the "Independent Director") who shall not have been, at the time of
his or her appointment or at any time in the preceding five (5) years and shall
not be at any time while serving as an Independent Director: (a) a direct or
indirect legal or beneficial shareholder of, or an officer, director, partner or
employee of, the Corporation or any of its shareholders, partners, subsidiaries
or affiliates, (b) a customer or creditor of, or supplier to, the Corporation or
any of its shareholders, partners, subsidiaries or affiliates, PROVIDED THAT,
notwithstanding any other language in this subclause (b), retail purchase of a
Werner product would not serve to disqualify an independent director, (c) a
person or other entity controlling or under common control with any such
shareholder, officer, director, partner, employee, supplier or customer, or (d)
a member of the immediate family of any such shareholder, officer, director,
partner, employee, supplier or customer (as used herein, the term "control":
means the possession, directly or indirectly, of the power to direct or cause
the direction of the management and policy of a person or entity, whether
through ownership of voting securities, by contract or otherwise); (iv) will not
take any action requiring the unanimous affirmative vote of 100% of the members
of the board of directors unless all of the directors, including the Independent
Director, shall have participated in such vote and all of such directors shall
have voted affirmatively (including the affirmative consent of the Independent
Director) to authorize such action; (v) shall maintain books of account in
accordance with generally accepted accounting principles and maintain its
accounts, books and records separate from any other person or entity; PROVIDED,
that the Corporation's assets and liabilities may be included in a consolidated
financial statement issued by an affiliate of the Corporation; PROVIDED,
HOWEVER, that any such consolidated financial statement will make clear that the
Corporation's assets are not available to satisfy the obligations of such
affiliate; (vi) will not commingle its funds or assets with those of any other
entity; (vii) shall hold its assets in its own name; (viii) shall conduct its
business solely in its own name; (ix) shall pay its own liabilities out of its
own funds and assets; (x) shall observe all corporate formalities; (xi) shall
maintain an arms-length relationship with its affiliates; (xii) shall not incur
any indebtedness other than unsecured trade payables and professional and other
expenses customary for a special purpose corporation engaged in transactions
with trade receivables in the ordinary course of business; (xiii) will not
assume or guarantee or become obligated for the debts of any other entity or
hold out its credit as being available to satisfy the obligations of any other
entity and will not permit any other person to assume or guarantee or become
obligated for the debts of the Corporation or hold out its credit as being
available to satisfy the obligations of the Corporation; (xiv) will not acquire
obligations or securities of its stockholders; (xv) shall allocate fairly and
reasonably (and pay or charge for, as applicable) overhead or other expenses
that are properly shared with any other person or entity, including without
limitation, shared office space and services performed by an employee of any
affiliate, if any, and use separate stationery, invoices and checks bearing its
own name; (xvi) will not pledge its assets for the benefit of any other person
or entity, except as provided for in the Purchase and Sale Agreement and the
Originator Assignment Certificate, pursuant to which a security interest would
be created in favor of the Corporation in the event that the purchase of Trade
Receivables by the Corporation is recharacterized as a secured loan and such
security interest would be pledged by the Corporation to subsequent purchasers
of the Trade Receivables, and the Receivables Purchase Agreement, pursuant to
which the Corporation would grant a security interest in the Trade Receivables
to subsequent purchasers thereof; (xvii) will 



                                       2
<PAGE>   3
identify and hold itself out as a separate and distinct entity under its own
name and not as a division or part of any other person or entity; (xviii) will
not fail to correct any misunderstanding known to it regarding the separate
identity of the Corporation; (xix) will not make loans to any person or entity;
(xx) will not identify its stockholders, or any affiliates of any of them, as a
division or part of the Corporation and will not identify itself as a division
or part of any entity; (xxi) will not enter into, or be a party to, any
transaction with its stockholders or their affiliates except in the ordinary
course of its business and on terms which are intrinsically fair and are no
less favorable to it than would be obtained in a comparable arms-length
transaction with an unrelated third party; (xxii) will maintain a sufficient
number of employees in light of its contemplated business operations; PROVIDED,
HOWEVER, that nothing herein will require the Corporation to have any employees
so long as employees are not necessary to the conduct of the Corporation's
business; and (xxiii) shall pay the salaries of its own employees, if any,
from its own funds.

        ARTICLE IV: AUTHORIZED CAPITAL STOCK. The total number of shares of
stock which the Corporation shall have authority to issue is three thousand
(3000) shares of Common Stock, $0.01 par value per share.

        ARTICLE V: INCORPORATOR. The name and address of the sole
incorporator of the Corporation is as follows:

        Kaye T. Walsh, c/o Gibson, Dunn & Crutcher LLP, 1228 N Street, Suite 5,
Sacramento, California 95814.

        ARTICLE VI: DIRECTORS -- NUMBER AND QUALIFICATION.

        Section 1. The Corporation shall have a Board of Directors consisting of
three (3) directors, which number may be increased or decreased hereafter in
accordance with the Bylaws of the Corporation. A quorum of the Board of 
Directors shall consist of two (2) directors.

        Section 2. The Corporation at all times shall cause there to be at least
one duly appointed Independent Director on its Board of Directors.
Notwithstanding anything to the contrary contained herein, such directorship
shall not be eliminated by reason of a vacancy. No Independent Director may be
removed unless his or her successor has been elected. The Independent Director
shall not at any time while serving as a director of the Corporation: (a) be the
legal or beneficial owner of either any stock of the Corporation or any of its
affiliates or of any interest in the Corporation or any successor thereof; or
(b) act as trustee-in-bankruptcy for any of the Corporation's affiliates or any
successor thereof.

        ARTICLE VII: ELECTION OF DIRECTORS. Elections of directors need not be
by written ballot unless the Bylaws of the Corporation shall so provide.

        ARTICLE VIII: BOARD POWER REGARDING BYLAWS. In furtherance and not in
limitation of the powers conferred by statute, the Board of Directors is
expressly authorized to make, alter or amend and rescind the Bylaws of the
Corporation. The Bylaws or any alteration, 



                                       3
<PAGE>   4

amendment or repeal thereof, shall not in any manner impair, or impair the
intent of, Articles Ill, VI, VIII, X or XI hereof.

        ARTICLE IX: CORPORATE POWER. Corporation reserves the right to amend,
alter, change or repeal any provision contained in this Certificate of
Incorporation (this "Certificate"), in the manner now or hereafter prescribed by
statute, and all rights conferred upon shareholders herein are granted subject
to this reservation.

        ARTICLE X: CORPORATE 0PERATIONS, BOOKS AND RECORDS. In addition to the
other provisions set forth in this Certificate, the Corporation shall conduct
its affairs in accordance with the provisions of Article III, Section 2.

        ARTICLE XI: VOTING.

        Section 1. So long as the Purchase Facility, as created pursuant to the
Receivables Purchase Agreement (the "Purchase Facility"), has not been
terminated according to the terms thereof, then notwithstanding any provisions
in this Certificate to the contrary or inconsistent herewith, the unanimous vote
of the directors of the Corporation (including the vote of the Independent
Director) in favor of approval shall be necessary for the Corporation to: (a)
approve any merger or consolidation, or any conveyance or transfer of all or any
substantial portion of the property or assets of the Corporation outside of the
ordinary course of business to any other entity in a single transaction or a
series of transactions; (b) amend the Corporation's Certificate of Incorporation
to alter the provisions of Article III, Section 2 of Article VI or of Articles
VIII, X, XI or XII; (c) take any action to dissolve or liquidate the Corporation
or windup the affairs of the Corporation; (d) seek relief under any federal or
state law relating to bankruptcy, insolvency, reorganization, the relief from
debts, or the protection of debtors generally; (e) institute proceedings to have
the Corporation adjudicated a bankrupt or insolvent; (f) consent to the
institution of bankruptcy or insolvency proceedings against the Corporation; (g)
file a petition or consent to a petition seeking reorganization or relief on
behalf of the Corporation under any applicable federal or state law relating to
bankruptcy; (h) seek or consent to the appointment of a receiver, liquidator,
assignee, trustee, conservator, custodian, sequestrator or any similar official
for the Corporation or a substantial portion of the property of the Corporation;
(i) make any assignment for the benefit of the Corporation's creditors or admit
in writing its inability to pay its debts generally as they become due; (j) take
any action, or cause the Corporation to take any action, in furtherance of any
of the foregoing (any of the above foregoing actions is hereinafter referred to
as a "Bankruptcy Action"); or (k) take any action that, by the terms of the
Receivables Purchase Agreement and the Purchase and Sale Agreement requires the
consent of the Independent Director. The directors and officers of the
Corporation shall be under no obligation to any shareholder of the Corporation
to take any Bankruptcy Action. Neither the Corporation nor any shareholder of
the Corporation shall have any claim for breach of duty or otherwise against any
director or officer for failing to take any Bankruptcy Action.

        Section 2. The Board of Directors shall not take any action requiring
the unanimous affirmative vote of one hundred percent (100%) of the Board of
Directors unless all 



                                       4
<PAGE>   5

of the members of the Board of Directors, including the Independent Director,
shall have participated in the vote.

        Section 3. To the fullest extent permitted by law, the Board of
Directors of the Corporation shall consider the interest of creditors of the
Corporation (other than affiliates of the Corporation that are creditors) in
connection with all corporate action.

        ARTICLE XII: LIABILITY AND INDEMNIFICATION.

        Section 1. To the fullest extent permitted by the Delaware General
Corporation Law, as the same exists or may hereafter be amended (provided that
the effect of any such amendment shall be prospective only) (the "Delaware
Law"), a director of the Corporation shall not be liable to the Corporation or
its shareholders for monetary damages for breach of fiduciary duty as director.

        Section 2. The Corporation shall indemnify, in the manner and to the
fullest extent permitted by the Delaware Law (but in the case of any such
amendment thereto after the date hereof, only to the extent that such amendment
permits the Corporation to provide broader indemnification rights than permitted
prior thereto), any person (or the estate of any person) who is or was a party
to, or is threatened to be made a party to, any threatened, pending or completed
action, suit or proceeding, whether or not by or in the right of the
Corporation, and whether civil, criminal, administrative investigative or
otherwise, by reason of the fact that such person is or was a director, officer,
employee or agent of the Corporation, or is or was serving at the request of the
Corporation as a director, officer, employee or agent at another corporation,
partnership. joint venture, trust or other enterprise. The Corporation may, to
the fullest extent permitted by the Delaware Law, purchase and maintain
insurance on behalf of any such person against any liability which may be
asserted against such person. The Corporation may create a trust fund, grant a
security interest or use other means (including without limitation a letter of
credit) to ensure the payment of such sums as may become necessary to effect the
indemnification as provided herein. To the fullest extent permitted by the
Delaware Law, the indemnification provided herein shall include expenses
(including attorneys fees), judgments, fines and amounts paid in settlement and
any such expenses shall be paid by the Corporation in advance, of the final
disposition of such action, suit or proceeding.


        IN WITNESS WHEREOF, the undersigned being the incorporator hereinbefore
named, for the purpose of filing the Amended and Restated Certificate of
Incorporation in accordance with the General Corporation Law of the State of
Delaware, has executed this Certificate as of May 27, 1998.



                                             ---------------------------------
                                             Kaye T. Walsh, Incorporator

                                       5