Your safest bet would be to reflash to stock PR1.3 and let the system notify you of the updates again. Reflashing is recommended anyway since you bought a used phone. Some people had either uninstalled Nokia link to save space or deliberately removed it so that they didn't get the update (in most networks the N9 functions just fine anyway)

To be more precise, Nokia link is a package that contains the software that allows connecting your phone to a windows or mac computer, and IIRC is preloaded in the mass memory of the N9 so that you don't have to download it. Nokia wanted to push some additional packages to all users without issuing a new PR so they piggybacked Nokia link to push them. (the Debian system Harmattan is based on does not have a way to notify the users of additional packages that need installing so they bumped the version number of an existing package and added new dependencies to it so that when you update it the new packages get installed)

I Might not be completely right about this but that is generally what I understood.