H.W.
I wonder if your little guy is overtired and hitting his second wind at his usual bedtime? I would try to put him to bed earlier...try moving it up a half-hour and see if he's still in that 'tired' window, or if you need to go earlier. I know we are 'earlier' than some families, but we do a 6:30 'get ready for bed', in bed by 7 with stories, lights out by 7:30 and Kiddo is up and happy around 6:15a.m. or so in the morning, ready to go.