QUOTE from Parallels blog:
Want in on the experience? Make sure you are running the most recent version ofParallels Desktop 9 for Mac, by going into the Parallels Desktop menu and click Check for Updates, and check to see if you have the most recent version. The program will automatically prompt you to update Parallels Desktop 9. If you are not currently a Parallels Desktop user, you can take advantage of a free 14-day trial, which will be the most recent version.
You can also watch Skeeter Harris, Tech Evangelist from Mac Village Media, walk you through his first impressions of Yosemite along with how Windows apps perform seamlessly thanks to Parallels Desktop 9 for Mac on Yosemite.
:UNQUOTE
Thank you for the comment.
The latter part of the blog quoted above and the Youtube video following it, ARE about "Parallels under Yosemite, but it seems to me that the former part of the blog quoted above is referring to experiencing Yosemite public beta under the latest version of Parallels 9
I may be wrong of course as English is not my first language.