There are several reasons why this game may not be completed in 2 versions. We don't actually know the intended versioning scheme Viit is using. Without knowing that, v0.9 is just as likely to roll into v1.0 as v0.99 is. As GrammerCop mentioned, the .99 could actually be only used to indicate progress in the updates prior to completion, so it's possible this would roll from v0.99 to v0.100 and then to v0.101, and so on.
It's also possible that, even if we roll over to v1.0 after the next release, the versioning just continues past 1.0. There are many software releases (such as of operating systems or web browsers) that don't actually have a public version that is considered complete until they pass v1.0. We might have another 5 updates and get to v1.05 or something. It's hard to know for certain.
I absolutely agree with you that if this is "complete" in two versions, either those versions will do very little to tie up loose ends (or do so badly), or they will be quite substantial in size. I doubt the latter of those would happen, so I really hope this goes beyond v1.0. I'd like Viit to avoid a Life with Mary wrapping up of the game. The things you mentioned all need to be resolved without rushing things. It would also allow for more content with the paths beyond Sandra, Adriana, or Haley (solo).