I can think of scenarios where this could work, but I would definitely rather have season 2 focus on the less explored relationships of the og 5 (things like KanoSumi and ChisaKeke). I haven't even finished season 1 yet and now I have even less interest in doing that...
yeah, like the one bright spot about more members, is that the OG 5 may get moments like the third years ot the first groups got at the end of the second seasons/movies, which are stuff I really liked, also I think this may increase the chances of superstar getting 3 seasons instead of 2.
That being said, I still really wish they had stuck with 5 members and keep developing those 5 and all the posible relationships between them... I've also started watching more stuff with the seiyuu of Liella and I really like the vibe they already have as a team of 5, who knows how that'll change with 9 of them now...
also some people seem to have the teory that a possible season 3 may introduc 3 more characters (one girl for each constellation) and at that point I am really terrified ^^;;;