The Samsung Galaxy S9 Android Pie update requires a sizable chunk of space on your internal storage. If you're running out of space, or even if you're not, use this time to cleanup your storage.
If you've owned your Galaxy S9 for a year, your internal storage is probably filled up with files and data you no longer need.
If you don't clean up your storage on a regular basis you'll probably be shocked by how much bloat you've got hanging around. Before you install Android Pie, make sure you dig into your storage and get rid of items taking up room.
You can use your Galaxy S9's Device maintenance feature in your Settings to help narrow down the list of items to delete.
If you do some cleanup you'll be ready for the Android Pie download and you might see a boost to your device's overall speed.