(a) Notwithstanding the provisions of sections 9-203, 9-205 and 9-206, any town may, by charter provision, provide for the election of a board of education consisting of not less than three nor more than twelve electors of such town for terms of two, three, four or six years. Each such town may provide in an ordinance or charter provision for method of rotation. Such ordinance or charter provision shall not take effect until six months after adoption. Members of boards of education shall first be elected in accordance with any such ordinance or charter provision at the next regular town election following the effective date of such ordinance or charter provision.

(b) No person serving an elected term to a board of education on the effective date of any such ordinance or charter provision shall have his term shortened or terminated by virtue of such ordinance or charter provision.