Hi David
At one time, it was a requirement to upgrade to a new install folder name (by default the version number is included in the install folder name). I do not know if this is 100% necessary for the latest releases but I still adopt that same policy just to be safe. My personal preference would be to perform upgrades of the App Server in-situ, but I don't believe that is currently supported by the installer.
About your tablespace, and assuming I can decode the meaning of DM_I1 / DM_D1, etc. , you have > 3GB available for the index tablespace and > 60GB spare for data tablespace (assuming you have space in the file sytem to autoextend to the Max limit) and also plenty spare in your staging tablespaces too. By coincidence, I have recently successfully upgraded from CCC 2.6 to 2.9 with ~3GB / 5GB availability in the main index and data tablespaces. This is not a cast-iron guarantee but I would not expect to see any issues with the upgrade due to your current tablespace constraints.
It would be in your interests to do a little bit of space auditing and tidying up of your DB and I would recommend doing this on a regular basis anyway. There are many factors that can influence that, and more knowledge of your environment and primary use cases would be needed before making any explicit recommendations, but the thing that raises the biggest flag is the constraint on the main datamart index tablespace. If I were you, I'd be looking to see what is consuming all the space in the index tablespace and taking action from there.
I think I recently posted the DM_Tablespace DA and associated CCR reports - did you get that set up and running?
HTH,
Adrian