Volume 9's setting seems to be based on the 1865 novel "Alice's Adventures in Wonderland" and its 1871 sequel "Through the Looking-Glass".
Three days after the final episode of the Volume airs on Crunchyroll, Justice League x RWBY: Super Heroes and Huntsmen, Part One was released.
The art direction for Volume 9 was inspired by M. C. Escher and other modern surrealist artists.This includes the volume poster which was inspired by Escher's 1946 work "Gallery."
According to Eddy Rivas, the idea of Volumes 7, 8 and 9 was always to end it with a more personal story focusing on Team RWBY, Jaune Arc and especially Ruby Rose herself as its climax.
The Volume 9 Opening Song, "Inside", was released as a single on the same day as the first chapter of the volume. This is the first time the full opening song was released alongside its corresponding volume.
The themes of Volume 9 according to RT Discord is "trauma, therapy, imposter syndrome, and emotional growth".
The episode names for the Volume appear to have a theme, just like Volume 8's only being one word except for the final episode. This time, the titles make heavy use of alliteration to create a sense of whimsy, followed by the episode description beginning with "In which...".
Concept art of Summer Rose implies that there were originally going to be more than ten episodes in the volume, as the concept art is labeled with "episode 11" as the episode it was made for.
An animatic of the Volume 9 Epilogue was shown to the attendees of the RWBY Panel at RTX Austin 2023. [19] The animatic was labeled "RWBY9_Ch12", indicating that Volume 9 was going to end with a 12th episode, and this animatic would've been the post-credits scene to close out the Volume. The scene was then stated by the crew to likely appear in some form at the start of Volume 10, albeit with obvious tweaks.
Eddy Rivas posted two images of the Epilogue's script on Twitter.