I think so. You probably won't be seated right at 7:30. Enjoy a before dinner cocktail, an appetizer, entrees, and be sure to order one of their delicious desserts . A dinner at the Ca Grille could easily last 1.5 to 2 hours. If you finish early, hang out in the lounge area to watch wishes. Dining at the Ca Grille during Wishes is one of our favorite things to do. Enjoy!
You should be fine. They normally run behind anyway, but even if they are on time when you're there, we had a 7:40 reservation a couple of weeks ago, were seated on time and we were just waiting for dessert when wishes started. It was perfect timing.
When I called Disney Dining for a Cali Grill reservation for our anniversary, the CM made our ressie for 6:10 and told us to request a window seat so we could see the fireworks. WISHES is at 8:00 pm that evening, so I'm sure you would be in the same situation we will be Have fun!
You should be just fine. Most likely you'll be near the end of your meal (assuming they seat you on time) or just having finished. Perfect timing to see Wishes either way.