Sec. 9. (a) A county property tax assessment board of appeals may:
(1) subpoena witnesses;
(2) examine witnesses, under oath, on the assessment or valuation of property;
(3) compel witnesses to answer its questions relevant to the assessment or valuation of property; and
(4) order the production of any papers related to the assessment or valuation of property.
(b) The county sheriff shall serve all process issued under this section which are not served by a county assessor and shall obey all orders of the board.