This might be a release dependent issue also...what NX9 release are you using?
Can i upgrade myself the latest release ?
Will "release upgrades" cause harm to other users opening same files or will NX 9-files still be NX 9-files for other users ?
You should be able to download the latest MP yourself, and install it. Unless your company denied you write access to the NX folder, it should just work fine.
And as long as you stay within a major release (NX 9.0 in your case) all files are compatible, from NX 9.0.0 to NX 9.0.3 MPxx and all what is in between. As soon as you go to NX 10.0 or higher, you get into trouble
this is not compatible with the version NX 9.0 of you colleagues anymore.