Currently Being ModeratedSep 12, 2013 11:44 PM (in response to kmccmk9)
Apple does not provide downloads for any complete OS later than OS 7.5.3. All downloads for OS 9.x and OS 8.x from Apple are updates only, which require a specified pre-existing OS version to be already installed before the update can be installed.
If you need OS 9.1, you can get if from sites like Hardcore Mac; unfortunately, their prices are high. Other possible sources would be an Apple User Group (most universities and larger sities have them); or perhaps Ebay or similar.
Note that if your machine needs a model-specific version of OS 9.1, no other version will suffice including a retail version. However, a retail version of OS 9.2.1 should work with such a machine.