Don't get me wrong I'd love to be wrong on this one, especially because September would've been the perfect time for me to play the game. However FFXV still having technical issues isn't sth. that just came up with the recent "rumour" , various people repotred it back at E3 and weeks before that.So it should not surprising at all that they finally decided to push the game back a few weeks.
Just don't get your hopes up at this point. I was sceptical as well when the rumour popped up because I've never heard of the site. That said if a site like Gematsu who already leaked the original release date back in march says that the same source which reported them the release date back then now confirmes that the rumour from Gamnesia is indeed true, combined with Jason Schreier from Kotaku who "incidentally" got the same info, I just don't have any reason to doubt the credibility of this "rumour" anymore.