Section 8A. A municipality, wherein a person resides who is admitted to a day school in another municipality under section 7, shall, through its school committee, when necessary, provide for the transportation of such person, and shall, subject to appropriation, be entitled to state reimbursement to the full extent of the amount so expended; provided, that such a municipality wherein a person is placed by the department of children and families or the trustees of the Massachusetts training schools who is admitted as aforesaid to a day school in another municipality shall similarly provide for the transportation of such pupil to such school and shall, subject to appropriation, be entitled to state reimbursement to the full extent of the amounts so expended; provided further, that no transportation shall be provided for, or reimbursement made on account of, any pupil who resides less than 1 1/2 miles from the school which he attends. A municipality shall not be required under the provisions of this section to provide for the transportation of a person who has completed the twelfth grade of school or the equivalent thereto.