Sec. 9. The 1937 fund and the appropriations made for the fund shall be used exclusively for the following:
(1) Payments to retired members and the dependents of deceased members.
(2) Death benefits.
(3) Other incidental expenses that are authorized by and are essential to the proper administration of this chapter, including the payment of all costs of litigation (including attorney's fees) arising in connection with the 1937 fund.
(4) Payments described in section 9.5 of this chapter.