This is a big question you’re asking. Young people aren’t just little adults. There are neural and physical development differences, and depending on the age group, their needs can be very different.
The gym where I work has minimum age requirements for youth attending fitness classes, so I don’t typically work with youth under 12. And what I teach is within my scope of practice as a group-ex instructor and a personal trainer.
No matter what population you’re working with, it’s always helpful to consider your scope of practice. What are you certified to do? What are you qualifed to do? What are you insured to do?