Your goal is to get to the gates and be in the front of the group waiting to enter, not the back. So you are at the front of the line to go to Pandora, not the back. This means less than 30 min wait to ride.
So you want to be at the AK turnstiles no later than 8:00, which means parked and through security. I'd plan to hit the parking lot about 7:30 myself. So I wasn't rushing. If you don't have bags to check you can cut down 15 min or so on that. If you plan to take Uber/Lyft, take off a bit more time since you are dropped right at the entrance.
Now, this means you are waiting more than an hour get in to Pandora and for them to open the ride. You'll have little to no wait after that, which means you safe lots of park time.
If you plan to do nothing but Pandora this may not really be the best use of time since you could arrive later and probably have about the same wait, you just spend more of it when the park is open vs when the park is closed.
It all depends on what else you plan to do.