Install for Night Mode
Night Mode is one of the big changes included in Samsung's new One UI and it's a great reason to install Android Pie right now.
When the Galaxy S9's Night Mode is active, the device's screen should be a lot easier on your eyes. It'll also help you conserve battery life.
When Night Mode is active you'll also notice changes across the user interface. Most stock Samsung apps including the Bixby Home UI are compatible with Night Mode.
You can manually turn Night Mode on whenever you want to use it. And now, thanks to an update, you can also automatically schedule when Night Mode turns on.
You'll find that option in the display settings.