It really depends. If you want to be die hard and get anywhere near the judges you'd need to be there at least 9:00 if not earlier.
Plus, without priority, it's very unlikely you'll be behind the judges or anything like that. They go around early and choose "the good looking ones" to be right behind the judges 'cause they'll be seen on TV a lot.
You should arrive at least an hour and a half earlier just to make sure you get in as well.
