Is this version capable of dealing with 4k video?
If not, what should I upgrade to?
Probably not as it's now years old and may have been released before 4K was available in vidcams.
As for upgrading unfortunately Vegas Movie Studio has been discontinued. 17 was the last version. It's not available from Magix but you may find some resellers still have it available. Or upgrade to Vegas Edit which is Vegas Pro without extras https://www.vegascreativesoftware.com/us/vegas-edit/. Your VMSP9 may qualify you for the upgrade price. There's a 30 day trial available.
Or there's the "new" Magix Movie Studio, which is Magix Movie Edit Pro renamed. It also has a 30 day trial but it's a different programme to Vegas Movie Studio.
I did download the 30 day trial of Magix and it seems to work fine. Just a matter of getting used to the differences. It took all my Vegas login info, so I'm hopeful it will be the upgrade price as well. We shall see soon.
THX
Going forward, please note that the MAGIX versions of Movie Studio (2022 and 18) are supported here: https://www.magix.info/us/video-forum/movie-studio/