a) Agreed; the fact that spaces aren't in the spec is annoying when trying to stay spec-compliant and not realizing you also have to search through various GitHub issues to be fully informed. Granted, spaces have been one of the most hotly-discussed topic in Matrix development for months, so anyone interested in making anything Matrix related likely would have come across it.

b) Not true; spaces don't require room version 9. IIRC the only space-related feature that needs a room upgrade is "restricted rooms", ie. the ability to make a room accessible only to members of another room/space.