What Does The Phrase "To The Nines..." Mean? Where Did It Originate?

There are a number of theories here, and apparently no widely accepted single one on the origin of the phrase.

Some think in modern times that it is mostly used as a rating scale (1-10), meaning 99999... Infinitely as close to perfect as possible.  Other theories have ranged from originating from Old English, "dressed to the eyes", which apparently would have been expressed as "to then eyes"-- but there are some problems with dates or origin there.

It seems there is no definitive answer, but here is a website where you can read some of the other theories.

To the Nines

It is used to indicate perfection - the highest standards. There are many thought about this phrase. It was in use in 18th Century. For more information about 'to the nines' visit the following link.
To The Nines

The origin is almost certainly British Army or Navy or Airforce. The meaning is 'dressed in your best uniform' and is still in use today in at least the Royal Air Force. (don't know about the others)
I belive it has something to do with dress code in " King's (or Queen's) Regulations", the set of rules by which all royal forces were controlled, but I can't verify that.
"Wear number nines" was a direction, when I was in the forces, for the dress standard for formal functions.
As we know, the term is used generally to mean 'dressed to kill' or 'all dressed up'.

I don't know the origin but I do know it means to get very dressed up-fancy duds and all