Well, the Galaxy S9 smartphone users in the US are still waiting for this important software update. Hopefully, the company will release the stable One UI update soon.
The software version of this update is G960FXXU2CSA2 and G965FXXU2CSA2 for the Galaxy S9 and Galaxy S9+ respectively. The size of the update is 1751.34 MB.
You can check for the update by heading into the Settings > Software update > Download updates manually.