What is the ruling on the late payment penalty imposed by an Islamic school on a Muslim father for delaying tuition fees, and is this penalty considered usury (riba)?

It is not permissible to delay or procrastinate in fulfilling an obligation. The owner of the wealth has the right to demand his money and to annul the contract. It is not permissible for the wronged party to take more than his due, unless it is in the form of a penalty in construction contracts (the agreed-upon penalty clause), or by order of the legitimate ruler to deter negligence in rights.