Sec. 9. (a) In making and supervising investments of the system, the board shall discharge its duties solely in the financial interest of the participants and beneficiaries of the system for the exclusive purposes of:
(1) providing financial benefits to participants and beneficiaries; and
(2) defraying reasonable expenses of administering the system.
(b) The board, in accordance with the fiduciary duties described in this article, shall make investment decisions with the primary purpose of maximizing the target rate of return on the board's investments.