According to
http://linuxwireless.org/en/users/Drivers/ath6kl , the driver (it's called "ar6003" on the Kindle) should in principle support ad-hoc mode. I guess that you will need to find the correct commands to make it do so, my first guess would be iwconfig.
If you find out how to do it, feel free to post your results here. Maybe I can include them in the file, so this could become an "enable officially unsupported Wireless modes" utility instead of an "enable WPA-EAP Wireless mode" utility only.