I think the gun matters far more. I do not shoot any gun as accurate as my CZ 75 in 40 S&W. of all the guns I shoot, the 2 I shoot best are in 40 S&W followed by 45 and lastly 9mm. It isnt a fair comparison though because of the platforms. CZ 75(40)>XDM 5"(40)>1911 4.25"(45)>XDS 4.25"(45)>HK VP9> Glock 19.
Disclaimer: I shoot the XDS far better than I aught to. At times I think I can shoot that better than my 1911, for some reason. For me, the triggers I am most comfortable with make the biggest difference. Give me a CZ in 9, 40 or 45 and I would assume I could shoot them all well.