Thanks for reaching out.
Have you tried to force stop and clear the cache on the camera app?
Navigate to your settings > apps > click the 3 dots in the top right corner > select "Show System Apps" > find and click on Camera app > force stop > storage > clear cache.
- Restart device.
Also, Try booting your device in safe mode to test the camera and see if the same symptoms still occur.
To boot your phone into Safe mode, start by pressing and holding the power button until the power menu appears on your screen. From there, long-press the "Power Off" button until it turns into a "Safe Mode" button. Simply tap on "Safe Mode" once it appears and your device will automatically reboot to safe mode.
- Test camera.
To exit out of safe mode, reboot device as normal.
Thanks for testing that for me. Can you send a private message here (http://bit.ly/2GGYul4) with the following information? Seems you may need a service repair on your Note 9.
1. Model Number
2. IMEI Number