So I have just created a windows 8 bootable drive using the tutorial at http://bleeptobleep.blogspot.fr/2013/02/mac-install-windows-7-or-8-on-external.html?m=1 But when I held down the option key at startup, it only showed Macintosh HD and Recovery 10.9.2 Then, I tried plugging in the drive to a different Mac and sure enough, it worked. After holding option, it showed the usb drive as a bootable option. Does anybody know why it was not working on my other Mac?
EDIT: I fixed the issue, thank you to everyone that took the time to help me. :)