Well it all depends on a few factors, at least to me.
1 how old is the snake
2 what is the weight of the snake
3 when did it last shed/ is it going into a shed
To me he looks young and not very large so I would put him at a 5-6 range if he has recently shed. But if he is going into a shed it's hard to say how bright he truly is. So he could be a 7-8.
He has nice blushing on his back, and good yellow along the sides, flames are decent. But he looks like he is starting to brown out at a very small size and his pattern isn't busy enough for me.
Regardless he is a beautiful heathy looking snake.