Is it possible to turn amarok's notifications on or off via dbus?

I've tried having a look at the methods exposed on dbus but unfortunately qdbus kept segfaulting (perhaps because I don't run the KDE DE) and so I've no way of finding out whether notifications can indeed be enabled/disabled via dbus.

Is it possible?

Probably, since I am not a developer I suggest you have a look at the code yourself. Of course to do anything in Amarok you should at least use the basic libraries Amarok uses, as stated in the README file, namely kdelibs