I got the update for my S9 last week. Never had any camera issues before that at all whatsoever. Now, suddenly, my camera shows a black screen, about everybthird time Ibuse the camera, and I have to restart my phone to get it to work every time. I tried to force stop the app, but that did nothing to help. The only thing that helps is to restart my phone. And I'm sick of doing that three times a day.
Same is happening to me and it's very frustrating... I tried to wipe the caches but the problem came back soon after. I would like Samsung to take action as my friends have the same problem with their s9. If only there is a way to go back to the previous Android version.
I had the same problem but fixed it by having my phone auto restart twice a week overnight. Follow the directions below or Google Samsung phone auto restart.