Below you can see the front view size comparison of Samsung NX1 and Sony A9. Sony A9 is clearly the smaller of the two cameras. Its body is 12mm narrower, 6mm shorter and 3mm thinner than Samsung NX1.
Samsung NX1 vs Sony A9 - Front View
Samsung NX1 vs Sony A9 - Top View
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.
Camera Size Comparison
Select Two Cameras for Size Comparison