While some newer Samsung flagships have already started receiving Android 10, Galaxy S9 series owners must wait a while longer to try One UI 2.0 on their devices. If you fancy a taste of Android 10 sooner than next year, then Samsung is planning to deliver a second beta build next week.
https://www.notebookcheck.net/Samsung-Galaxy-S9-Second-Android-10-beta-available-next-week.446059.0.html