I'm not gonna lie, Occultic;Nine's anime adaptation is indeed fast. Fast as in very fast in every single angle, that if you haven't read the original light novel nor the manga of it, then you'll end up scratching your head trying to understand why and what on each episode that you're watching. Well, some anime are built to be like that and I'm pretty sure that A-1 picture did a very good job adapting the content into an anime.
Having a quite score at myanimelist, I don't think that the fans would like to abandon the anime of Occultic;Nine but when it comes to every trailing season especially season two, there will always be problems up ahead. The possibility of this anime to have a second season is low unless there would be enough volumes from the original light novel. The series is still young though, there's still a lot of room to cover and that goes with the manga too.