Sec. 9. (a) Unless the articles of incorporation provide otherwise, if a vacancy occurs on a board of directors, including a vacancy resulting from an increase in the number of directors:
(1) the board of directors may fill the vacancy; or
(2) if the directors remaining in office constitute fewer than a quorum of the board, they may fill the vacancy by the affirmative vote of a majority of all the directors remaining in office.
(b) If the vacant office was held by a director elected by a voting group of shareholders, only the holders of shares of that voting group are entitled to vote to fill the vacancy if it is filled by the shareholders.
(c) A vacancy that will occur at a specific later date (by reason of a resignation effective at a later date under section 7(b) of this chapter or otherwise) may be filled before the vacancy occurs but the new director may not take office until the vacancy occurs.