Hi Luisa,
It's so tempting to try to pack activities back-to-back to get everything into your Walt Disney World vacation. While I think it could be possible to get to Magic Kingdom for
Wishes (assuming it is at 9 p.m.) after a 7:30 p.m. dinner at
Chef Mickey's, I'm afraid you would feel rushed throughout your meal and wouldn't enjoy it to its fullest.
I like to allow at least 90 minutes for dinner, especially when characters are involved. Please remember that even though you have a reservation, it's possible you won't be seated right at 7:30. And you want to be sure you have time to visit with Chef Mickey and his friends as they come to your table for pictures and autographs.
I'd also allot at least 30 minutes to get from the Contemporary to a prime spot to view Wishes. It's just about a 10-minute walk from the Contemporary to the entrance to Magic Kingdom, but you'll need to go through the security check and tap your MagicBands or cards to enter. Again, I never like to feel like I'm racing on my vacation, especially after a big meal.
If you can't get a reservation at 6:30 or 7 p.m. (which I think would be optimum for returning to Magic Kingdom for Wishes), you might want to think about an alternate viewing area such as the observation deck on the fourth floor of the Contemporary on the end closest to Magic Kingdom. That's super convenient from Chef Mickey's.
You can also view Wishes from the Transportation and Ticket Center or the beach at the Polynesian Village Resort, though getting there may not be faster than returning to Magic Kingdom.
I hope that helps with your scheduling, Luisa. Please let us know if we can answer any other questions for you. Enjoy!
Wilma