The spy chord - a history.?

Aah yes, the spy chord, possibly one of the most Iconic chords of all
time. Just one chord is a powerful motive in itself, bringing one back
to memories of James Bond movies.

What is the spy chord, you ask? Well, another name for the chord is
the Minor/major 9th chord, and if you just play that on the piano
right now (C Eb G B D) you now know exactly what I'm talking about
with this spy chord business.

So, I have a few actual questions about this chord.

A. What piece (or song) is the earliest to feature this chord? Was it
from a spy movie? Jazz? Classical?

B. What makes this chord so iconicly "secret agent-ish"? Is it just
our association with it's use in spy movies, or is there something
characteristic about the chord that gives it this quality? (or are
both factors at play?)

C. Do you know of any other chords this iconic? If you do, what makes
this/these chord/s so iconic?

Plus, you can add any other information you deem necessary.

Have fun!

Bonus Q; What about iconic chord progressions? While a I-V-vi-IV
progression might not make too many listeners say; "Hey, this song
sounds a lot like song X!" The progression from pachabel's canon in D
is often unmistakable in any context.