[Added 2006-10-15: Another potential fix here...]
[Added 2006-09-19: Additional things to try here...]
[See other posts about 0x8ddd0009 here and here.]
Microsoft just posted knowledge base article 924092 today - "You experience problems when you use a Microsoft update service".
The CAUSE section states:
These problems may occur because some of the Windows Update Agent 2.0 files are missing or corrupted. Windows Update Agent 2.0 is required to use these products and services.This could be another way to fix the mysterious 0x8ddd0009 Windows Update / Microsoft Update error - intall the "Windows Update Agent 2.0" package.