Can I safely use root for I9500, if I have a GT-I9506? Can I safely use root for I9500, if I have a I9506?
Or will it cause any problems?
If not, what root can I use?

I can't seem to find the I9506 anywhere on the internet. Is it a new edition or is it because it's nordic?

EDIT: Bear with me I'm new to android.
If you're thinking of Chainfire's CF-Auto-Root, don't use the files for I9500, I9505, I9505G. Chances are it might not work.

However, XDA has a thread with a pre-rooted GT-I9506 stock ROM. You can try that instead.