Jojo I did it with Aurora actually. If you're using the manual download method, as described, it will automatically suggest the last version before the current one (9.9 in this case), so the version number provided is the one you need. I had to uninstall the Google camera app first, because an in-place downgrade was not possible.
EDIT: the version number for 9.9 is: "68469120" btw, in case someone else needs it.