Not for free, or strictly legally, not both at the same time anyway.
You can find copies of Mac OS 9.1 shared on the web on some of the same sites that list serial numbers, junk your 9.2 System Folder and use the system you downloaded instead. Panther will complain that it works best with 9.2, but it will work anyway, just ignore the invitation to update.
I have left some hints for you in the previous paragraph, refer to my friend Google for further information.
Edit: A better solution would be to buy a used OS 9.1 CD on eBay, it should cost less than $5.