Interesting. As far as I can see, Apple hasn't released El Capitan yet. I know its on tap for today, but its not showing up anywhere yet - not in MAS, not on Apple's website.
Very interested to hear how this works for people. I'm still at 9.73. I didn't move to 9.8 as it looked like there were a few problems. Hoping that is all resolved in 9.81.
In the same boat as @rcorbin here. We hung on 9.73, partly because 9.8 was mostly for iOS 9 support and we don't manage iOS devices with our JSS. But we'll definitely need to update to 9.81. Any reports on how its working for folks, any issues and such would be great to hear about.