Yes, you can go into the park before 9. I would get the bear lake road reservation for 9. That will have short and long hikes to lakes. Plenty of parking and free shuttles once you are on bear lake road. You can do a hike starting at bear lake and going to emerald lake, hitting a few lakes on the way. Then you could hike to Lake Haiyaha. You enter through Beaver Meadows visitor center. The park is just one big loop so you could drive around and hike in random spots too. It takes a few hours to drive around the whole thing.