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.
Teens age 16 through 18 years can get the booster dose at any time. The minimum interval between doses is 8 weeks. However, teens who receive their first dose of quadrivalent meningococcal conjugate vaccine at or after age 16 do not need a booster dose.