Saw a forum reference to xPUD (http://xpud.org) as a lightweight OS to run on my Mini 9. Downloaded and installed it to a bootable 64 MB flash drive.
I changed BIOS options on the Mini 9 to allow booting from USB. Then I deleted syslinux.cfg, and renamed isolinux.cfg to syslinux.cfg.
Moment of truth. The Mini booted in about 30 seconds (maybe less). The entire OS loads into RAM (not SSD, the RAM) and then boots from RAM. This setup is amazingly fast. I can leave the default boot setup as Win XP, and boot xPud whenever I want. I am impressed.