I removed the SD Card and all issues were resolved.
My issues were that on multiple shooting modes the camera app would crash or the view finder screen would freeze.
It works fine now. I hope this is useful.
Thanks @SkyUk! :robothappy:
For folks looking for the later ongoing discussion about S9|S9+ and SD Card issues, please check out this thread.
Click here to see 'How to set up Emergency SOS on your Galaxy Smartphone'