I'm curious why are you thinking of running the 18-50 on the S9? is it only for 50/60P ?
As for your main question... we really don't know enough, I'm also curious if Lumix follows the body design of the S1 series, or if it's a new body, or they re-cycle the S5ii body. (I don't think that is likely)
Hopefully we'll know by end of month.