Bus operators will often find it economical to convert retired buses to use as permanent training buses for driver training, rather than taking a regular service bus out of use. Some large operators also converted retired buses into tow bus vehicles, to act as tow trucks.
Explain to an 8 year old child that is not yet 49 tall that the safety equipment built into the vehicle is for adults  not children, and a child needs to continue to use the proper equipment (booster seat) so that the adult equipment will fit, and be able to protect, their bodies in the event of a crash.
Booster seats are generally for children weighing 40 to 120 lbs. Boosters should be used until a child is at least 57 inches tall, the minimum height at which a car's seat belts will fit him or her appropriately, typically between the ages of 8 and 12 years.