CDC will be powered via SAM I think, to allow it to continue to operate when the ignition is off, and also I presume it comes alive when you open glovebox, even if the engine is off, so you can eject / insert CDs?
If your dashcam takes 12V, it is very easy to hard-wire it (not much more complicated, if it's 5V either) - you can pick a switched positive from the power socket fuse (better) or directly from the power socket wiring - all you need is a fuse tap (or inline fuse holder, if splicing the power socket wire), some quality wire and some Tesa tape ... Just make sure the power socket is not permanently live (some rear ones are - mine is, for example).