We stayed there in May and got there between 9 and 10 am. We went to check in and did all the paper work and stuff. They gave us our room keys even though the room wasn't ready yet and said they would text or call us when the room was ready if we wanted to go to the parks. We checked our bags and headed off for a day of fun.
So whatever time you get there, go check in as they will get you set up even if the room isn't ready. Also if you didn't book a park view room ask them how much it would be to get one. You may just get a free upgrade like we did. But I find the odds are better if you act like you might be willing to pay for it and aren't asking to be given something free. If they don't upgrade you for free and quote you a price you can just say no thank you if you don't want to pay it.