E.F.
Is he still taking naps? If so, that needs to be cut out. One of my sons (who is five and going to kindergarten in the fall) is a night owl. We put him to bed at 8:30 and he is still up sometimes at 9:30 or later. This past year I put him in P.M. preschool because he easily sleeps until 8:30a.m. Does your little guy sleep in? I think when fall comes with the consistency of waking up earlier and then going to bed the same time he will get used to falling asleep earlier. Start putting him to bed earlier and waking him at the time for preschool two weeks prior (in a perfect world) to starting school. This helps getting them adjusted.