There's a new set of documents available for Acrobat and Reader 9. While the page title refers to Reader, the documents themselves apply to both Acrobat 9 and Reader 9. The documents provide guidance and important information regarding changes in Acrobat and Reader 9 that may affect enterprise workflows.

If you are a Reader user or administrator, I recommend you start with the Adobe Reader 9.0 Compatibility Overview document, and then review any of the other documents that are likely to affect your specific organizational workflows.

If you are an Acrobat user or administrator, skip the overview document but review the rest.

Acrobat and Reader9 compatibility documentation