The rollout has begun! France is the first country that the update reached. The update T835XXU2BSD1 includes Android 9 Pie software, App Actions, Slices and One UI interface. For now, the update is only available for the LTE model of the tablet; Wi-Fi model should receive its own variant of the update at any moment.
If your device does not download the update automatically, you need to go to Settings > Software Update > Download Updates Manually.