Yeah, on Vista and above the Nirtools add a "blocked" registry value which Opus 9 doesn't know about. Opus 10 will see it.
That's usually fine, and is similar to what Nirtools does on XP and below (it renames the InProcServer value instead, from what I remember). It's vaguely possible that it will take out more than just the shell extension, though, if the same COM object (represented by the CLSID) implements more than just a shell extension.
A better way to block a shell extension by CLSID is to add it to Opus's blacklist: Go to Preferences - Miscellaneous - Advanced and double-click the ignore_context_menus setting. A small window will appear into which you should paste the CLSID values, including curly braces, of the extension(s) you want to exclude, one CLSID per line.