If you are seeing 931125 being reoffered via WSUS it’s due to the fact that the May 2009 update is not properly marked at “HasSupercedingUpdates” which is messing up the offering of the September update causing it to be reoffered. Decline both the Feb and May 2009 update in WSUS.
Then on the workstation if you are getting it still reoffered you have to clear it out of the software distribution folder.
Per Chuck on the SBS2k list -- To recap the fix for others. 1. Went to WSUS and manually declined both of the updates. 2. Stopped the Automatic update service on the affected workstations. 3. Deleted everything in C:\WINDOWS\SoftwareDistribution. 4. Restarted the automatic update service. 5. Restarted the work stations.
(edit ... you can also delete out just the cert folder under that softwaredistribution folder and just chuck that out the door)