I don't know about the Wheeler and Wilson 9, but all of the other machines you mentioned take a "normal" 15x1 needle.
You can find these everywhere - even in some grocery stores. They're also called 2020, HAx1, 130/705 and other names, depending upon the manufacturer.
Get the regular sharps, (they're so standard that the package will probably not even say "sharps" on it) not universals or "stretch" needles. Only use ball points if you're sewing knits. I get Organ and Orange brand by the hundred on eBay for about $13-15/100.