S.,
I've been there, and you have my sympathy. I agree with some previous advice about finding out what he eats at daycare and also strongly advise taking him to a specialist to check for ADHD or other issues.
My son is also very active and athletic and bright. He had trouble sleeping and sitting still long enough to eat. He was referred for testing by his preschool, and diagnosed with Sensory Processing Disorder. The therapist told us his body craves extra sensory input. She gave us activities to do throughout the day and before bedtime to help fill that need for sensory input so his body could relax and fall asleep. She also had us put light ankle weights on him at night to help him sleep. He's still not the world's best sleeper, but it did improve.
It was also reassuring to talk with the therapist and find out which of his traits were common in children with sensory-craving issues (athleticism, sleep issues, and eating issues are all common), and to find out why some of the "standard" suggestions for helping children sleep weren't working for him and sometimes made it worse. He, too, could cry and scream for hours, so I quickly gave up on the "cry it out" method. He could be put back to bed over and over again with no change in how frequently he woke up in the night. Making his room dark and quiet, trying to calm him down before bedtime, and other things actually made his sensory cravings and his sleeping worse. My husband works out of town often, too, and accused me of NOT doing those things to try to help him sleep, so it was becoming a source of tension for us.
Getting the proper diagnosis and understanding what to do about it (requires no medications, just some therapeutic activities and NOT doing some of the standard things) has been a huge help for us. My son is doing better. I get more uninterrupted sleep at night and don't feel so tired at work during the day, and I feel much better. I hope you can find some answers soon, too.
Good luck!