Adobe has released the ColdFusion 9.0.1 Hotfix 2, available on the update page. This is a cumulative hotfix, containing fixes for security issues, items around ORM, resolution to questions of JSON serialization, integration bits for Exchange, and much more.
Install has some quirks. It's not just a simple 'upload the file' bit, so you'll want to pay careful attention to the instructions, and backup affected files in advance. This will get so much easier with the next version of ColdFusion, but for now it's worthwhile to jump through the hoops. It is a 'cumulative' hotfix, and word from those in the know say that it is safe to skip over the CHF 1 install, if you haven't done it already, as all it's changes are within this hotfix as advertised.