<PAGE>   1
                                                                    EXHIBIT 10.9



                              INLAND RESOURCES INC.
                             STOCK OPTION AGREEMENT

         This Stock Option Agreement ("Agreement") is entered into effective as
of October 1, 1999 between Inland Resources Inc., a Washington corporation (the
"Company"), and Bill I. Pennington, an employee of the Company (the "Employee").

                                   Recitals:

     The Company desires to grant to the Employee a Nonqualified Stock Option to
purchase shares of its Common Stock, $0.001 par value, pursuant to the terms and
conditions of this Agreement.

                  The parties agree as follows:

         1. Grant of Option. The Company hereby grants to the Employee the right
and option (the "Option") to purchase all or any part of an aggregate of 875,000
shares (the "Shares") of its Common Stock, $0.001 par value, on the terms and
conditions and subject to all the limitations set forth herein.

         2. Purchase Price. The purchase price of the Shares covered by the
Option shall be $0.9375 per share.

         3. Vesting of Option. Subject to the other terms and conditions of this
Agreement, the Shares exercisable upon exercise of the Option granted hereby
shall vest in accordance with the following schedule: (i) 10% shall vest on each
of the first four anniversary dates of the date of this Agreement if Employee
continues to be employed by the Company on each such anniversary date, and (ii)
the remaining 60% shall vest on the fifth anniversary of the date of this
Agreement if Employee continues to be employed by the Company on such date.

         Any non-vested Shares under the Option granted hereby shall be deemed
to have



                                      -1-
<PAGE>   2

immediately and automatically vested on a "Change of Control", as such term is
defined in the Employment Agreement between Employee and the Company entered
into effective as of the same effective date of this Agreement.

         4. Exercise of Option. Subject to the other terms and conditions of
this Agreement, the vested Shares granted pursuant to this Option may be
exercised at any time during the term of this Agreement in accordance with the
terms of paragraph 7.

         5. Term of Option. The Option shall terminate on the fifth (5th)
anniversary of the date that the last Option granted hereunder vested, but shall
be subject to earlier termination as provided herein.

         6. Non-Assignability. The Option shall not be transferable by the
Employee otherwise than by will or by the laws of descent and distribution and
shall be exercisable, during the Employee's lifetime, only by the Employee or
his or her guardian or legal representative. The Option shall not be assigned,
pledged or hypothecated in any way (whether by operation of law or otherwise)
and shall not be subject to execution, attachment or similar process. Any
attempted transfer, assignment, pledge, hypothecation or other disposition of
the Option or of any rights granted hereunder contrary to the provisions of this
paragraph 6, or the levy of any attachment or similar process upon the Option or
such rights, shall be null and void.

         7. Manner of Exercising Option and Issue of Shares. The Option relating
to vested Shares may be exercised in whole or in part by giving written notice
to the Company, together with the tender of the Option purchase price. Such
written notice shall be signed by the person exercising the Option, shall state
the number of Shares with respect to which the Option is being exercised, shall
contain any representation required by paragraph 8 below and shall otherwise
comply with the terms and conditions of this Agreement. The Company shall pay
all transfer or original issue taxes



                                      -2-
<PAGE>   3
 with respect to the issue of the Shares pursuant hereto and all other fees and
expenses necessarily incurred by the Company in connection herewith. Except as
specifically set forth herein, Employee acknowledges that any income or other
taxes due from him with respect to this Option or the Shares issuable pursuant
to this Option shall be the responsibility of Employee and that the Company may,
in accordance with the Internal Revenue Code, require Employee to pay additional
withholding taxes in respect of the amount that is considered compensation
includable in Employee's gross income. Employee shall have rights as a
shareholder only with respect to any Shares covered by the Option after due
exercise of the Option and tender of the full exercise price for the Shares
being purchased pursuant to such exercise.

         8. Purchase for Investment. Unless the offering and sale of the Shares
to be issued upon the particular exercise of the Option shall have been
effectively registered under the Securities Act of 1933, as amended, or any
successor legislation (the "Act"), the Company shall be under no obligation to
issue the Shares covered by such exercise unless and until the following
conditions have been fulfilled:

         The person(s) who exercise the Option shall represent to the Company,
at the time of such exercise, that such person(s) are, acquiring such Shares for
his or her own account, for investment and not with a view to, or for sale in
connection with, the distribution of any such Shares, in which event the
person(s) acquiring such Shares shall be bound by the provisions of the
following legend which shall be endorsed upon the certificate(s) evidencing
their option Shares issued pursuant to such exercise:

                  "THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE BEEN
         ACQUIRED FOR INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER THE
         SECURITIES ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY
         STATE. WITHOUT SUCH REGISTRATION, SUCH SECURITIES MAY NOT BE SOLD,
         PLEDGED, HYPOTHECATED OR



                                       -3-
<PAGE>   4

         OTHERWISE TRANSFERRED, EXCEPT UPON DELIVER TO THE COMPANY OF AN OPINION
         OF COUNSEL SATISFACTORY TO THE COMPANY THAT REGISTRATION IS NOT
         REQUIRED FOR SUCH TRANSFER OR THE SUBMISSION TO THE COMPANY OF SUCH
         OTHER EVIDENCE AS MAY BE SATISFACTORY TO THE COMPANY TO THE EFFECT THAT
         ANY SUCH TRANSFER SHALL NOT BE IN VIOLATION OF THE SECURITIES ACT OF
         1933, AS AMENDED, OR APPLICABLE STATE SECURITIES LAWS OR ANY RULE OR
         REGULATION PROMULGATED THEREUNDER."

         Without limiting the generality of the foregoing, the Company may delay
issuance of the Shares until completion of any action or obtaining of any
consent, which the Company deems necessary under any applicable law (including
without limitation state securities or "blue sky" laws).

         9. Notices. Any notice to be given under this Agreement shall be deemed
sufficient if addressed in writing, and delivered by registered or certified
mail or delivered personally, in the case of the Company to its principal
business office and in the case of the Employee, to his address appearing on the
records of the Company, or to such other address as he may have designated in
writing to the Company.

         10. Governing Law. This Agreement shall be construed and enforced in
accordance with the internal laws, and not the laws of conflict, of the State of
Colorado.

         11. Benefit of Agreement. This Agreement shall be for the benefit of
and shall be binding upon the heirs, executors, administers and successors of
the parties hereto.

         12. Adjustment of Shares. Wherever this Agreement specifies a number of
shares of Common Stock or a purchase price per share, the specified number of
Shares of Common Stock to be received on exercise and the applicable purchase
price per share shall be changed to reflect adjustments (which may require that
additional securities or other property be delivered on exercise) required by
this paragraph 12, as follows:



                                       -4-
<PAGE>   5

                  (a) If an increase has been effected in the number of
         outstanding shares of the same class of securities of the Company as is
         issuable upon exercise of this Option by reason of a subdivision of
         such shares, the number of Shares which may thereafter be purchased
         upon exercise of this Option shall be increased with respect to each
         Share issuable upon exercise of this Option by the number of Shares
         which could have been received by Employee at the time of such
         subdivision had he been the holder of record of such issuable Shares at
         the record and/or effective date of the subdivision. In such event, the
         purchase price per Share under this Option shall be proportionately
         reduced.

                  (b) If a decrease has been effected in the number of
         outstanding shares of the same class of securities of the Company as is
         issuable upon exercise of this Option by reason of a reverse stock
         split, the number of Shares which may thereafter be purchased upon
         exercise of this Option shall be changed with respect to each Share
         issuable upon exercise of this Option to the number of Shares which
         would have been held by Employee at the time of said reverse stock
         split had Employee been the holder of such issuable Share at the record
         and/or effective date of the reverse stock split. In such event, the
         purchase price per Share shall be proportionately increased.



                                      -5-

<PAGE>   6

         EXECUTED effective as of the date and year first above written.


                                              INLAND RESOURCES INC.

                                              By: /s/ Michael J. Stevens
                                                 -------------------------------
                                              Its:   Vice President

                                              EMPLOYEE:

                                              /s/ Bill I. Pennington
                                              ----------------------------------
                                              Bill I. Pennington



                                      -6-