I see 9 is on iOS, though it's 21 dollars. I have 3 thru 6 on Android (as well as Tactics, Dimensions, and 4: The After Years), but haven't finished 3 yet.
I got most of those when they were on sale; most cost about 16 fish normally. I'll have to keep watch for a discounted 9. And I wonder if 8 will be coming to mobile?