Unless otherwise provided by special act or charter, (1) members of boards of assessment appeals, (2) selectmen, (3) town clerks, (4) town treasurers, (5) collectors of taxes, (6) constables, (7) registrars of voters, (8) subject to the provisions of subsection (i) of section 10-223e, members of boards of education, and (9) library directors shall be elected, provided any town may, by ordinance, provide for the appointment, by its chief executive authority, of (A) a constable or constables in lieu of constables to be elected under section 9-200, or (B) a town clerk, town treasurer or collector of taxes in lieu of the election of such officers as provided in section 9-189. Unless otherwise provided by special act or charter, all other town officers shall be appointed as provided by law and, if no other provision for their appointment is made by law, then (i) by the chief executive officer of such municipality, (ii) where the legislative body is a town meeting, by the board of selectmen, or (iii) by such other appointing authority as a town may by ordinance provide, and except that, if a board of finance is established under the provisions of section 7-340, the members thereof shall be elected as provided in section 9-202. Any town may, by a vote of its legislative body, determine the number of its officers and prescribe the mode by which they shall be voted for at subsequent elections.