Hey Penney!
You will be able to enter the Magic Kingdom early so that you can arrive on time for your reservation. It's a good idea to arrive about 15 minutes before your actual reservation and to bring the reservation number, just in case!
When you come up to the gates you'll see other early diners arriving and there will be an entrance open for you.
I love walking down Main Street towards the Castle before the Park is officially open...you can really see and enjoy all of the details that sometimes get lost in a crowd.
Disney transportation coming from Disney Resorts does operate very early for guests to make early reservations. However, the hotel that you mention is not on Disney property so I don't know about their shuttles. I looked at their website and it mentions a shuttle leaving at 8:20am! I suggest giving them a call and ask about how they can help you. Hopefully, they have an earlier shuttle for Guests with breakfast to attend!
Thanks so much for thinking of the Disney Moms Panel when you had a question! Your trip is almost here!