After exclusive software update for Hong Kong, Samsung is now rolling out a new software update for the international Galaxy Note 9 units. The latest software update brings the December 2018 security patch. It doesn't bring any camera/feature improvements.
It is based on Android 8.1 Oreo, not on the One UI beta. The software version of this update is N960FXXS2ARL3, and the size of the update is 63.09 MB.
If you want to check for the update manually, you can check for it by heading into Settings > Software updates.