Hiya, Susan!
If a restaurant shows breakfast until 10:15, that means the latest reservation they will take is one for that time. No one is kicked out until they are finished, so you wouldn't need to worry about that at all.
Cinderella's Royal Table is a great spot to go after your little one gets a princess make-over at the
Bibbidi Bobbidi Boutique. She'll be all dolled up with her special hair and pixie dust, and the restaurant is the place to go to schmooze with the other royal princesses. So many little girls take the opportunity to live out their Fairytale in exactly this way.
Make sure when you make your appointment for the Bibbidi Bobbidi Boutique, you make it for the one located at Cinderella Castle in the
Magic Kingdom theme park. There is another location in
Disney Springs. Even with the awesome Walt Disney World transportation, it would be pretty tight to make it to a breakfast at the Castle after a 9 AM appointment in Disney Springs.
Have an absolutely magical time on your upcoming visit, Susan!
Anna