BIOS password is to prevent bios changes from unauthorized people. If F9 is for "boot device"-selection and boot device selection is allowed by bios settings it works. Why you don't just try it
Or is "boot device" selection not enabled in bios and you don't know the bios password? Are you sure it's F9?
"boot device" selection must be enabled. And "boot device priority" (or something like that) must list pendrive as well! boot device selection just lists the allowed boot devices