I already posted this on the other thread for this but I guess I will put it here too. It's supposedly being revealed in January at the Detroit Auto Show, http://www.autoblog.com/2015/11/20/volvo-s90-detroit-auto-show/.There are unauthorized source saying that at least one S90 has been made in Daqing factory in China. However it is kept in confidential.
Not sure what Volvo is waiting. Maybe in holiday season too many key people are on vacation to prepare for a media press event.