Do kid models or kid actors make more money?

Only if the child actor or child model is able to book consistent work and snag the biggest jobs. If a child actor gets booked for a recurring role on a TV series for example, then he/she can stand to make a lot of money, especially if merchandising and commercials are involved. Child models can make a lot of money if they happen to book ad campaigns for big name clients. But they don't necessarily make more money than adult models.