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                                                                       EXHIBIT 9

                           14951 North Dallas Parkway
                              Dallas, Texas 75240

                                                                January 23, 2000

GRUPO SANBORNS, S.A. de C.V.
Av. San Fernando 649
Colonia Pena Pobre, Tlalpan
Mexico, D.F. 14060
Mexico

Dear Sirs:

     We expect to provide certain information concerning CompUSA Inc. (together
with its subsidiaries, the "Company") to Grupo Sanborns, S.A. de C.V. ("Grupo
Sanborns") and its affiliates, including, TPC Acquisition Corp. ("TPC") (all
such affiliates, together with Grupo Sanborns, "you"), in connection with the
Merger Agreement, dated the date hereof, between the Company, Grupo Sanborns and
TPC (the "Merger Agreement"). All such information, whether written or oral,
furnished to you or your Representatives (as defined below), now or in the
future, by or on behalf of the Company (whether prepared by the Company, its
advisors or otherwise), together with analyses, compilations, studies or other
documents or records prepared by you or your Representatives which contain or
otherwise reflect or are generated from such information, are collectively
referred to herein as the "Evaluation Material."

     In consideration of the Company's furnishing you with the Evaluation
Material, the Company and you agree to the following (it being understood that
you are also agreeing to cause your affiliates to comply with the provisions
hereof):

          1. You will use the Evaluation Material solely in connection with the
     transactions provided for by the Merger Agreement and not in any way
     directly or indirectly detrimental to the Company. All Evaluation Material
     shall be kept confidential by you, except that you may disclose the
     Evaluation Material or portions thereof (i) to the extent required in any
     legal proceeding or by applicable laws, regulations or other legal
     requirements in connection with effecting the transactions provided for by
     the Merger Agreement (including in filings made with regulatory authorities
     or required to be disclosed in tender offer or proxy materials) and (ii) to
     those of your directors, officers, employees and advisors (the persons to
     whom such disclosure is permissible being collectively called
     "Representatives") who need to know such information solely in connection
     with the transactions provided for by the Merger Agreement (it being
     understood that, before disclosing the Evaluation Material to such
     Representatives, you will inform such Representatives of the confidential
     nature of the Evaluation Material and that, by receiving such information,
     they are agreeing to be bound by the terms of this Agreement). You agree to
     be responsible for any breach of this Agreement by your Representatives. In
     the event that you or any of your Representatives becomes legally compelled
     (by deposition, interrogatory, request for documents, subpoena, civil
     investigative demand or similar process) to disclose any of the Evaluation
     Material, you shall provide the Company with prompt prior written notice of
     such requirement so that the Company may seek a protective order or other
     appropriate remedy and/or waive compliance with the terms of this
     Agreement. In the event that such protective order or other remedy is not
     obtained, you shall furnish only that portion of the Evaluation Material
     which is legally required and shall use your reasonable best efforts to
     obtain assurance that confidential treatment will be accorded such
     Evaluation Material.

          2. The term "Evaluation Material" does not include any information
     that (a) at the time of disclosure or thereafter is generally available to
     and known by the public (other than as a result of a disclosure in
     violation of this Agreement directly or indirectly by you or your
     Representatives), (b) was
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     available to you on a nonconfidential basis from a source other than the
     Company or its advisors, provided that such source was not known by you to
     be bound by a confidentiality agreement regarding the disclosing party, or
     (c) has been independently acquired or developed by you without violating
     any of your obligations under this Agreement.

          3. Upon any termination of the Merger Agreement, you will, upon the
     request of the Company, destroy or return to the Company all copies of the
     Evaluation Material in your possession or in the possession of your
     Representatives.

          4. The term "person" as used in this Agreement will be interpreted
     broadly to include, without limitation, any governmental authority,
     corporation, company, partnership, limited liability company, joint
     venture, trust or individual. The provisions of Sections 9.02 through 9.06
     of the Merger Agreement shall be deemed applicable to this Agreement as
     well.

     If you agree with the foregoing, please sign and return a copy of this
letter, which will constitute our agreement with respect to the subject matter
of this letter.

                                          Very truly yours,

                                          COMPUSA INC.

                                          By:
                                          --------------------------------------
                                            Name:
                                            Title:

Accepted and agreed as
of the date written above.

GRUPO SANBORNS, S.A. de C.V.

By:
- ---------------------------------------------------
    Name:
    Title: