does 1password 4 for windows work on parallels for mac

It does! Several of us use it in VMware virtual machines, and several others prefer Parallels.

Whichever you choose, treat the virtual machine as a separate physical machine. Specifically, if you're planning to sync between the Mac and Windows in the virtual machine, avoid the "shared folder" feature that maps Desktop to Desktop, Documents to Documents, and so on; install Dropbox on the Mac and in Windows on the virtual machine, and let Dropbox sync your 1Password data between them, as if they were separate physical computers.