Many years ago I watched S9 to figure out why it sucked so bad. It was the absolute lack of character growth. The end of S8 all kind of wrapped everything up nicely, JD and Elliott finally got their shit together, JD finally grew the fuck up, Dr Cox finally chilled out... It was a beautiful wrap.
Then S9 threw it all in the trash, Cox was back to being an asshole and JD was all nerdy and insecure again.
A reboot can absolutely work provided its more of a continuation than a reboot. If they show me JD like he was 20 years ago like nothing happened in that entire time and trot out old jokes it will suck.