Samsung released the Android 10-based One UI 2.0 update for the Galaxy S9 and S9+ last week in the US, but only for the carrier-locked units. Now, the company has expanded the rollout for the unlocked S9+ units as well. The firmware for the unlocked units sports version number G965U1UEU7DTA5 and weighs around 1.9GB in size. It brings in all the features of Android 10 and One UI 2.0 and bumps up the Android security patch level to January 2020. The update is rolling out over the air and should hit all the devices soon. But those get impatient can try checking for the update manually...
Source: https://www.gsmarena.com/samsung_galaxy_s9_s9_plus_android_10_us_unlocked-news-41352.php