I just upgraded from Cubase 8.5 Pro to 9 and found that none of my settings were transferred.
Did I do something wrong during installation (whether 8.5 or 9) ? Considering that Cubase 8.5 is still intact, is there any way to transfer those settings/preferences to 9, after the fact?
Any advice is appreciated.
You did nothing wrong… sometimes the preferences transfer and sometimes not. There are quite a few posts about this similar concern.
One thing you can try is to copy the 8.5 preference files to 9.
The attached link is the location and use of the files to copy. Good luck.
Regards. 
Yikes! That’s a lot of XML files, and I’m not confident they’re compatible between versions (unless Steinberg explicitly promises they are), so I’ll probably play it safe and rebuild everything by hand. Grrr…
Probably a better bet for stability anyway. Back when I updated from C6 to C7 things went completely crazy. Ended up having to delete the C6 prefs to make C7 work right. It is weird that it works sometimes, and others not.
This recent upgrade to C9 transferred everything correctly. But I am still working on projects in C8.5 so not doing anything til I need to.
Best!
Check out this link:
https://www.steinberg.net/nc/en/support/knowledgebase_new/show_details/kb_show/cubase-and-nuendo-program-preferences-files-in-detail.html
It gives you an overview of all the setting files and where you can find them.
I would try to copy the most important ones and see if it works. If there are any problems, you only have to delete them and restart Cubase. It will then create the default ones instead. Good luck!