R9 will start with the protagonist rescuing Rias, and will end with her moving in the protagonist's house. In the anime, that would be the end of season 1.
There'll be some progress with Akeno as the outlines suggest, but more importantly, we're getting very close to the point where the protagonist finally begins his relationship with Rias and Asia.
The scene is actually already written (just a rough sketch), I just need to find a good point where to put it (ideally, as soon as possible, but without making it feel forced).