I had a -8.5 not even sure how you get to -9 as it appeared to be as short as it could get. Its a good hull, not as nimble for flatwater as a KDX or DVX IMO I owned a KDX next and have ridden MANY DVX's but it is more stable and glued to water than either of those. The downside is it didn't pop off setup wakes as well and the nose being flattened across bottom front made it really rough to handle in chop when chasing boats (center keel removed throughout the rockered section on bottom). It is not a bad hull at all. Its my 3rd favorite of all that I have owned or ridden really. T1 which combines the DVX and Badass being my favorite then the DVX and 3rd the -8.5 carbon Badass. The new Helium seems to be a nice option, I have very little time on one and seems to need me to adjust my ride style a little but the wider hull feels super stable where the DVX was tippy on recoveries.
Read the T1 review for more opinions if your interested, but these are simply my opinions. Again its a nice hull but not the best IMO. If your interested in ONLY Flatwater from my experience it is hard to beat the XScream hulls, for a mix of both there is nothing I have ridden that does it better than the T1.
A friend has a gorgeous KDX for sale with pole which for the $ is a great flatwater hull and this thing is MINT if interested PM me for his #, the hull is at Tricky's in AL having the drive train removed to be installed in his new T1.
The hull is incredibly clean and plug and play.