Okay so Sarah Shepard has come out with a 9th PLL book, Twisted (even though she said that the 8th -Wanted- would be the last). I haven’t read it yet, but I think that she should have ended the series after Wanted. The ending of Wanted tied up every loose end in the series. Plus, they figure out who A is, so I’m not sure how they’ll go on from that… Personally, I think she’s dragging on the series (which I don’t understand why she has to do because she’s started a new series that’s also being turned into a TV show - The Lying Game - and it’s really good). So yeah, that’s my opinion.
You can read about the book/series here.