from whence does the expression come?
No one knows and it is subject to a great deal of thought and research.
http://www.nytimes.com/2012/12/27/books/the-whole-nine-yards-seeking-a-phrases-origin.html?hp

One interesting comment is that "yards" is not 36 inches or three feet but short for "yardarms" and a Captain of yore would call out "Give me the whole nine yards" when wanting to make full sail.. ya think??