volume 9 seems to be more slice of life
volume 10 is undercovering the back story that we've been hinted in volume 8, stuff like why hiyori became a ghost, lost memories and that stuff
There's quite a lot to spoil on but nothing really related to yuri relationships. If you just want yuri fanservice, consider the live action film, there's literally like 20 minutes worth of it in it at the end and the entire film,
but like the adaption of "the cute iron maiden / chotto kawaii iron maiden" (edit: my bad it never really had plot to begin with lol, I remembered it wrong) they're quite literally just adult fanservice films and have very little actual plot.
The action film of imocho goes very far off plot though and you're rushed through a lot of details and iirc it had like 3 important scenes relating to the manga only.