SECTION 9. High school tuition of children under control of department of public welfare, etc.

If a city or town where a school age child is placed or kept under section seven does not maintain a public high school offering four years of instruction, said school age child may, subject to section six of chapter seventy-one, attend the public high school of another city, town or regional school district, but the commonwealth shall under section seven reimburse the city or town where he is so placed or kept, for tuition paid by it on his account.

Said reimbursement shall be based on appropriate documentation filed by the superintendent of schools of said city or town, as required by the commissioner of education.