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 try Android Pie right now.
When the Galaxy S9's Night Mode is active, the device's screen should be a lot easier on the eyes. You'll also 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. You can also schedule when you want the device to turn Night Mode on and there's also a way to set it so the device automatically turns it on when you're in the dark.