@djshaunyg: Sorry to hear that you're having battery issues with your Galaxy S9. I recommend charging your phone to 100% using your official charger, using the phone as you would normally so it drains to 50%, then going to Settings > Device Care > Battery > Battery Usage. Here you can see which apps are using the most battery, and disable the apps you don't frequently use, when they're not in use. I also recommend the following steps.
- Enable Power Saving mode
- Reduce your screen brightness
- Switch off GPS, WiFi and Mobile data when not in use
- Delete any recently installed 3rd party applications