I read a fishing report recently where the guy caught a good sized wild one on his 9wt. He was using a 10' sage xp...I have this same set up so took it out with my pin and tried it...I put a small about of weight on and had a hard time controlling my cast, granted it was without a float which would have added weight so that might have helped...It was a very light and manageable to carry, the gentleman said he has fished his for a couple years now and his friends do as well...My major concern is the snake guides...I would be concerned about trashing a really good fly rod when you can buy some decent pin rods for half the price...
Also we could get into the fact that what is the point really in fighting a steelhead to near death on such a light rod??? I love to ask this question because on my fly sites so many guys practice C & R, that I can't understand the point in undergunning yourself so you can enjoy fighting a fish so long it's chance of survival after you release it is near nill???
There are many affordable pin rods out there, until your really accomplished at it, I would ask, Why? more then Why not?...