1) can we use existing UF 8 (and 7) scripts on an
UF 9 install? Without modification?
2) Is there any change to the install procedure for UF 9?
3) Is there any change to the upgrade procedure from UF 8 to UF 9?
(UF 9 presumably has to be located in its own directory and cannot
be run at the same time as any other UF version that is running.)
1) If by scripts you mean rule files, yes they are compatible.
2) The install steps are the same, tar x, ufsetup.sh, license.sh, but the ufsetup.sh script now looks for the Apache web server and also prefers to set up an 'unform' user to run the server, so there are some more questions. This is documented in the manual. I'm assuming you are talking about Unix/Linux.
3) Yes, install in different directories (a critical requirement!); no, they do not conflict so you can run older versions at the same time. Default ports are different so they don't conflict. If you use direct tcp/ip printing into unform, however, different versions can't share the same ports.