Please pay attention that this solution is a work around and the formal full IE9 compatible support is from the IBM Lotus Quickr for Domino 8.5.1 Fix Pack 34, Domino Server build 8.5.3fp1 (18.104.22.168, build number 22.214.171.124-302a).
For Quickr 8.5 and 8.5.1 version:
1.Creating an HTTP Response Header rule document "X-UA-Compatible" to overwrite the Server response header with a custom value. Response Header rules can also be useful if you want custom headers to be sent from the server. These headers can then be read and possibly set to new values by your applications.
The Domino server can overwrite HTTP response headers if your application needs to do so. To create one of these rules, open a Web site document from the Internet site view of the server's address book. Select Web Site-> Create Rule as shown in the following figure.
2.On the Basics tab (see the following figure), change the Type of Rule field to be HTTP response headers. Then configure the fields as shown in the figure.
3.Add the value for rule, such as the following picture.
4. Restart Domino server and visit the quickr place.
5. If everything is OK, then you can see the the document mode is IE8 standards when press "F12" in IE9. It means the quick is running in the IE8 mode.
For Quickr 8.2 and lower version:
This meta tag tells the Internet Explorer to behave like an IE8. The database is replaced by every update and you have to do these steps again.