After doing all the upgrades noted above, I was unable to sync my photos to either my iPhone or iPad. The sync would stop with an unknown error 1140 message. I tried all kinds of things, including deleting the iPod Photo Cache folder, restoring the iPad software and setting it up as a new device, and rebuilding the iPhoto library. If I unchecked the sync photos option in iTunes the sync would run to completion (but of course not sync any photos!). There were two other oddities in all this. First, when I would check the iTunes box to sync photos, the option to select specific events was greyed out. Also, even though there appeared to be no photos on the iPhone or iPad, the little disk usage bar in iTunes would show a couple GB of space allotted to photos. Clearly something was hosed.
The only way I could finally get things working was to pull a pre-iPhoto 9.4 photo library off of Time Capsule. I also deleted the iPhoto 9.4 application from the Applications folder and pulled the previous version of iPhoto off of Time Capsule. Now both the iPad and iPhone will sync properly in iTunes again, the disk usage seems right and the option to choose what photos to sync is no longer greyed out.
But now I don't really want to upgrade to iPhoto 9.4 again. Anyone have similar issues or thoughts about what the problem might be?