I was searching Amazon and found this listing.
http://www.amazon.com/Winx-Club-Collection...words=Winx+Club
It's published by "Perfect Square" which is confirmed to be a branch of VizKids. Considering the fact that each Winx Comic Volume is roughly 95 pages and this is listed to have 832 pages, I think its safe to say that this is all the Viz comics crammed into one. This could also confirm that vol.9 is as far as Viz goes.