If you have a child who hasn't read the parenting book!!! you have to develop a thick skin. My 9 year old is not asleep now and it's 10:15 pm. She is in Yr 4, top of her class, Grade 3 on violin, does gym etc etc. You can't say she's not coping... she has friends... she just doesn't go to sleep at 8pm. I wouldn't even try to get her in bed at 8pm.... I send her up about 9. It gets easier... she can read etc.
The funny thing is, when she's at sleep overs, she's often the first to go to sleep (at around 1 am). It's like when she sleeps, she sleeps!!!!
She does a lot of exercise (4 hours gym and 1hr 45 mins of dance a week) outside of school... and if she doesn't have this, she sleeps even less!!!
If your son is developing well... I'm sorry... he just doesn't meed the same amount of sleep as other children!!! Not fun for you... so good luck.