I'm personally hoping it's a PS4 thing, is Sony having a conference for TGS? I also think it could be unveiled in famitsu around the time of TGS(or at least I hope).
It should be stated the event on the 9th is actually a general product event. Sony does a good job giving some amount of time to all their platforms currently on the market in their conferences. Their focus is on PS4, but I'm sure PS3 and Vita will be mentioned as well, just as usual.
So, could be either.