To be clear, I expect that "number" in "followed by zero or more word characters (alphabetic, underscore or number)" means "if Unicode thinks it's numeric, you can use it in an identifier after the first character."
I don't expect that every numeric codepoint in Unicode must evaluate to number in the Perl6 settings. We can have Numeric::Roman, Numeric::Counting-Rod, Numeric::Euler etc. for those, if someone cares enough to write & use them.