I have just updated to WatchOS9 and when i lift my wrist I get a very annoying flickering when the display lights up. Is it possible to switch it off?

Hello OwenDPaver,

Welcome to Apple Support Communities. 

Which iPhone is paired to your Apple Watch? What is the exact iOS version installed on your iPhone?

Please use the steps as listed here to restart your Apple Watch: Restart your Apple Watch - Apple Support

1. If your Apple Watch is charging, take it off the charger.
2. Press and hold the side button until you see the power button  in the upper-right corner of the display.
3. Tap the power button.
4. Drag the Power Off slider.
5. After your watch turns off, press and hold the side button again until you see the Apple logo.

Please use the steps as listed her to restart your iPhone: Restart your iPhone - Apple Support

1. Press and hold either volume button and the side button until the power-off slider appears.
2. Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
3. To turn your device back on, press and hold the side button (on the right side of your iPhone) until you see the Apple logo.

Let us know if you have further questions.

Take care.