Welcome to Justanswer.com, my name is ***** ***** I will do my best to assist you.
I just handled this issue the other day.. Quark 9 can run on yosemite, the issue is the installer tries to tell you that you dont have the right version of mac osx..
if youd like, I can connect to your mac from here.. And get 9.0 installed and working, so you can then use the 9.5 upgrade.
Would you like me to connect and repair this issue for you? Or, would you prefer to have me try and guide you through written support instead?