Well see that's the problem, the OP asked a meaningless question. He said: "should I use an eight inch or a nine inch knife," and got three pages of nerdy nonsense extrapolating the poignant differences between 8, 8.5, and 9 inch knives as if they were somehow founded in reality. The extra inch of length does not increase your edge's longevity, unless you are a idiot savant who manages to wear the entire edge at the exact same rate; it does not take any extra room to wield, because it's an inch, and if an inch of steel makes or breaks your ability to use a knife, you shouldn't use be using a knife (seriously guys, just choke up on it a bit); and lastly, it only might increase the weight--perhaps between two otherwise exact models--but I butter toast with a 300mm gyuto that weighs less than my 8" Wusthof, so there's clearly some grand generalizations being made here....and answering directly to what the OP asked, I still say 225 is the way to go...
The only people who ask if they should use an eight inch or a nine inch knife are people who don't understand what they're looking for in the first place, and it's therefore the last thing those people should be worried about.