Samsung is now expanding One UI/Android 9.0 Pie rollout to the Galaxy Note 9 in more countries. Samsung is now rolling out the stable version of its One UI (Android 9.0 Pie) to the Galaxy Note 9 users in Australia and South Korea. It also brings the January 2019 security patch.
In South Korea, the software version is N960NKSU2CSA1, and Australia has software version N960FXXU2CSA2.
You can check for the update by heading into the Settings > Software update > Download updates manually.