Hi Karen,
Welcome to the Disney Parks Moms Panel! If there were a grandparent of the year award, you would win it. What a wonderful trip you are planning!
The good news is that there are a few options. On my last few visits, I used Uber services. The prices were affordable and the service quick. Last summer when we stayed at Disney's Polynesian Village Resort Hotel, we also used a taxi twice. There were always one or two taxis waiting near the entrance to the resort hotel in the morning when we needed to get to early breakfast reservations. I would suggest that you allot at least 45 minutes to get to your breakfast reservation at Chef Mickey's.
If you want to try something super cute, use the
Minnie Van™ Service. Once you check-in at your resort hotel, ask a cast member about the service and he or she can assist you with getting it set-up. Since you have eight people, you would need two vans. You could also check the
bus transportation schedule when you arrive. Buses typically start running 45 minutes prior to park opening. Depending on what time Magic Kingdom opens, you could potentially catch a bus to Magic Kingdom and then walk or take the monorail to Disney's Contemporary Resort. Honestly, I am not sure you would make it to your reservation on time, but it is possible depending on the bus and
resort monorail service schedules for the day you arrive. If the resort monorail is not operating, you can walk to Disney's Contemporary Resort from Magic Kingdom. The walk takes about 10 minutes.
Karen, my family adores Chef Mickey's! Be sure to take your autograph books!
Magic, memories and Minnie Mouse hugs,
Donyell