There have been multiple reports that AT&T, Sprint and T-Mobile have started rolling out Android 9.0 Pie to the Samsung Galaxy S8, S8+ and Note 8. The OS update, which Samsung calls One UI, is being released along with the March 2019 security update.
https://www.notebookcheck.net/The-Samsung-Galaxy-S8-series-and-Note-8-have-started-receiving-Android-9-0-Pie-in-the-US.415639.0.html
Except Note 8 on Tmobile.
Tmobile always has to be the different baster step child and screw over its customers.
Pitty that they couldnt make it stable in Europe, got my update about month or more ago, since then, typing gets terribly slow once in a while, app switching gets stuttery once in a while, the phone feels slower at times.