G.B.
For a 3 yr. old he's going to bed awfully early. I would continue the nap for as long as possible. He will just end up fighting it when he starts school and they still have nap time. We are having to go pick up our grandson at noon due to him not napping. They lay down for an hour and since we pick him up that means he misses an hour and a half of class time in the afternoon.
He is also old enough to start doing activities like soccer and T-Ball. Sometimes the games don't even start until 7pm. I'd start letting him stay up later. Especially since Summer is always hard. It is still sunny at even 9pm sometimes.
That's just my opinion, he is growing and needs to start adjusting his bed time to a later time and still needs to nap every day for as long as possible.