9's are reasonable for some people cuz their playability is affected badly with higher gauges .
Just to add something , since I've been used to 10's for a long time , now my technique gets very sloppy (specialy the picking) when I play on a guitar strung with 8's ... just as people used to 8's get sloppy when they play 10's .
So it's just a matter of getting used to a certain gauge , and humans usualy adapt to anything very fast.
That's why I don't think it's a good idea to sacrifice the tone for the playability , which is something anybody can get used to in a short period of time.
