I've never seen them open the park early for breakfast people. During busy times, they usually open early, otherwise it's 9am. I think the character breakfast in IOA is at Confisco's, which is near the front on the park.
I agree that the first two hours are important to get that early bird start on the rides. You can tour the entire park getting walk on rides staying one step ahead of the crowd. By 11am, forget it, everyone is there and the lines are long. Of coarse, this doesn't matter too much if you are staying onsite and have UEPs.
Reviews of the character breakfast are mixed, depending on how much attention your kid gets. If your kid gets lots of attention and you take great pictures, then you'll be happy. If you get little attention and they forget about you (it's happened), then you'll walk out frustrated and say the food was bad and wasn't worth the money you paid. I'd say it could go either way.