Your camera focus mechanism is most likely broken, it is trying to zoom in and out, there's no other way to fix it on your phone, you must get a new rear camera and replace the one you have. Any questions? Ask me.
@SamsungJoJo I have the exact same issue. The amount of issues reported on this is insane and seems to be a common issue.
I have an email out to support but they are asking me to clear cache, clear data, run safe mode. All of this doesn't matter, it's a hardware issue. Can I get a PM also because email support is pretty useless. This is my only phone and I need to figure out a way to get this fixed and somehow not be without a phone for days.
I have the exact same issue, I think this is a factory defect, I love Samsung, I love my note9 and I hope this can be fixed either a free service/replacement or discounted deal. Is there any other solution you find out yet?