Our support policy is for the current version of any product and the one previous. As we are currently at Acrobat XI (11), that means that we dropped support for Acrobat 9 - a little over a year ago (http://blogs.adobe.com/security/2013/06/reader-9-x-reaches-end-of-life.html).
The correct way to do this would be to use the Javascript bridge available in Acrobat (and documented with samples in the SDK) with its Bookmark object.
