We check this website, now usbkill.com is up and dont blocked for our system and other users of the Internet.
So, answer to question: Is usbkill Down Right Now? - NO! usbkill is up!
If you have problem with access to site usbkill, and domain usbkill.com is not avalible.
Clear browser cache and/or try other web browser
(Chrome, Firefox or Safari).