One UI 2.0 beta program has been live for Samsung Galaxy Note 9 devices in South Korea. So One UI Beta 2.0 or Android 10 should also be live in US soon for Samsung Unlocked Note 9 devices. As per report Samsung Galaxy S9/ S9 Plus devices will also soon get One UI Beta 2.0 or Android 10 within next week in South korea and should release in US soon after for Samsung Unlocked S9/ S9 Plus devices . So just keep checking Samsung Members app for more information and for registration button, inorder to join beta program.
It's good to hear that you're ready to join Beta program try new features early and give suggestions and bug reports which will help Samsung deliver the best quality Official Software updates. Yep it's pretty exciting as One UI 2.0 or Android 10 will bring pretty awesome new features to Note 9 and Galaxy S9/S9 Plus devices which are currently only in One UI 1.0. Beta maybe little buggy but will let you get early access to new updates which add many new features and Improvements to the devices.