There are a lot of questions... Which Salmon R. - NY? How big is the 11 year old (height, weight)? I don't know how long he handled the rods, but a full day's fishing may tire him out, and you don't want to do that, or he will lose interest.
In addition, if it's the Salmon in NY, in the fall, a 6-wt would definitely be too light - too many Chinooks present!
I think I'd be a little conservative here - maybe get him a 9' - 8 or 9 wt., in case of salmon, and BIG steelies, and a good reel to balance it with. Besides, it could always be his "backup" rod when he gets bigger, stronger, more stamina and gets a longer "lifetime" rod.