Some kids do need less sleep. As long as they are not tired I wouldn't be worried. They will grow up needing less sleep too. Many famous people are like that and they have more time to accomplish things they want to do.

I do think you might be able to give melatonin a try if you want to shift his sleep schedule a bit. Our pediatrician thinks that is very safe for kids. I got a 300mcg version that seems to be effective.