people in this thread seem to have missed that they appear to be continuing the storyline from the "current" point in time, at least in so much as there will be an Empire and Colonies, which is to say there will be 9 clans. Whether they are all mechanically represented, and how that happens, is anyone's guess, but hoping to back to Clan Wars era 7 or what have you is wishful thinking.
the only way we get any number != 9 is by going forward, which will by necessity start with 9.
Just because clans exist, even retaining their great clan status, doesn't mean they have to be represented as a clan in the game. It's trivially easy to come up with story reasons for a great clan not to be terribly concerned with whatever the conflict in question is.
(And again, this leaves room to add clans in expansions.)