Personally, I'd be at the airport not long after 6am to allow time for check-in, security, immigration, security (again) and getting to your gate. I arrived at 8:40am for an 11am flight and was comfortably on time but the queue for immigration was pretty short. Other times it's been a lot longer.
The queues for check-in can be pretty horrific - check-in online if you can.
Also note that there's almost no place to eat once you enter the USPC area so if you want breakfast, you'll need to get it before then.