Sec. 9. PROOF OF CONTINUED DISABILITY. (a) The board may at any time require a person receiving a disability pension or receiving death benefits as a disabled child under this article to undergo a medical examination by a physician appointed or selected by the board for that purpose.

(b) A person retired for disability under Section 6(c) of this article or a person receiving death benefits as a disabled child under Section 7 of this article must file an annual report of employment activities and earnings with the board. The board shall establish the form of the report and the time for filing the report.

(c) The result of the examination, the report by the physician, and the report of employment activities and earnings shall be considered by the board in determining whether the relief in the case shall be continued, increased if less than the maximum provided, decreased, or discontinued. The board may reduce or entirely discontinue all benefits to a person receiving benefits under this article who, after notice from the board, fails to appear for a required medical examination or fails to file the report of employment activities and earnings.