Because of a NDA of some sort, the Acrobat 9 support was never in the 9.3 beta program and even missed the 9.3 release. But never fear, you can download the patch to enable Acrobat 9 support:
Adobe Acrobat and Adobe Reader version 9 support a new version of PDF that allows for encoding of map coordinate system and georeference information inside the PDF file. This patch enables ArcGIS Desktop, Engine, and Server applications to export georeferenced PDF files.
There also appears to be some sort of agreement where Adobe will support GeoPDF in their Arcobat releases. My head hurts a little after reading those press releases (note to everyone, stop using the word “consume”). Hopefully TerraGo will use their blog to actually tell us in English what this agreement means.