Take away toys, and just start bringing him back to his room any time he escapes. By letting him in your bed with you, he is learning that he is rewarded for getting out of bed (I've been there, we had the same issue with my 6 year old and 9 year old).
Repeatedly returning him to his room might be a pain in the butt, and very tiring for a few days, but he'll learn that bedtime means stay in your bed.
We didn't do that with my 9 year old and she still has sleep issues. We did with the 6 year old and he now stays in his bed and usually goes to bed great too.