The highest rating is a Master's rating. In all honesty, before you select a coach attend some freestyle sessions, watch the coaches as they instruct, see if their style is amiable to your child and your wishes, talk to other parents, ask questions of the coaches. Decide for yourself who would be best for your child and then make the selection. Always remember that a selection of a coach is your choice to make along with your child. If in the future you find that maybe another coach may be better for your situation, discuss it with your current coach and then you make the decision.
Coaches understand that some skaters change coaches while others stay with coaches.
If you look at some of the top skaters in the country you can see even at that level coaching changes happen.