i started the game as a Khajiit, so he can't wear any boots. then i went and found Pemenie and got the Boots of Blinding Speed off her, but i can't equip them. is there a script or command that allows me to force him to wear them?

There's a mod in circulation that makes the Boots of Blinding Speed into greaves. Do a search at Morrowind Summit for "Blinding Speed."