I think it really depends on how much of boost / hype the console gets from Watch_Dogs as well as bundles... If they do some heavy advertising then it could easily get 8.5... I'd say closer to 8 though judging by current trends in the sales.
I don't know because it's been roughly a million sold per month this year so far. Even in months I though it would fall. So it seems hard to figure out what the sales trend will be like. I do think watch dogs will boost it for may though. I still am gonna go with ~9 million.