Most accurate 9mm's in my safe...is a tossup between 2 guns....
a. Wilson Combat, 5" gun, 1911 obviously, in 9mm ...1" guarantee at 25 yds...and I shoot it a lot ...in any number of tactical drills...out of a holser, double taps, reloads, etc... A Protector model,in all stainless, with ambi safeties, mag well and night sights on it will cost you about $3,000. Mine has close to 40,000 rds thru it ( its about 5 yrs old ) and its still as accurate and as smooth as the day it came out of the box.
b. Sig 226 X-Five ...in 9mm or .40S&W...they are a single action only gun / depending on which version you buy. The top end one is around $ 2,300 or so, and it has an adjustable trigger in it. I have mine set at about 2.5 lbs... Its way to heavy to carry / its around 55 oz with a full mag in it...and its a high end - competition level gun / all stainless, wood grips. Nice gun....and a gun that will do a 1" group at 25 yds...
I lean toward the 1911 a little ...but I like the X-Five a lot as well.