Hi Lynette,
Yes, the Disney Princesses are present during Breakfast, Lunch and Dinner at
Cinderella's Royal Table.
Breakfast is held daily from 08.05am - 10.40am. If you make a dining reservation for between 8.05am - 9.00am on a day when the Magic Kingdom is due to open at 9.00am (and there are no Extra Magic Hours available from 08.00am to 9.00am for Guests staying at Disney Resort hotels) you will indeed be able to enter the Magic Kingdom before the park officially opens.
My family love to do this as it is a great way to get some fantastic photographs on Main Street U.S.A and in front of Cinderella Castle without there being any other Guests in the background.
Cinderella's Royal Table is one of the most popular restaurants at Walt Disney World so if you would like to dine here during your stay, I would highly recommend making an advance dining reservation at your earliest possible opportunity. Reservations can be made up to 180 days prior to your visit online
HERE or by calling (407) WDW-DINE or (407) 939-3463.
Wishing you a magical trip!