I'm developing some guesses on the events of Canto 10 and I'm gonna share a few ideas I've had
1: Meursault didn't directly kill his mother Immediately after reading The Stranger I really didn't like the idea that Meursault had killed his mother, but I like the idea that rather he was held responsible for the death of his mother. Knowing his background with N Corp there is a possibility that he was forced to kill her to show his commitment or something similar but I'm not as into this idea.
2: The Chaplain from the end of The Stranger being and Index member.
Blindly following prescripts is reminiscent of blindly following the commandments of the bible. The Index will likely be introduced in canto 9 with Ryoshu's connection to the 5 Fingers so it would be interesting to have them present in canto 10. This is probably just bias because I love the index, as it's more likely the Chaplain will just be a high up N Corp member as they also have a lot of religious imagery.
3: Raymond will be present in 9.5
It makes sense in my head that Raymond would be the one to initiate the events of Canto 10 as he did with the Arab man in The Stranger. He may possibly be a member of Demian's crew but that's just a shot in the dark.
4: Not canto 10 but next Walpurgis will be about the Shi Association.
The next Walpurgis should be for Ruina and I don't think they'll add any of the fingers from SOTC until canto 9 to coincide with the events happening, and the Shi make sense as an Urban Nightmare group to add as they're pretty popular. I have a feeling it may be like Walpurgis 3 where there's only one ID, probably Yujin. The 3 sinners without a 000 ID from Walpurg are Meursault, Ishmael, and Gregor. I believe Meursault will be the one to get the ID because of his similarities with Yujin, being quick to follow the commands of their leader without question. Ishmael will likely get a Little Red Riding Hooded Mercenary ID on the following Walpurg, and possibly Snow White's Apple or Schadenfreude for Gregor