Below you can see the front-view size comparison of the Panasonic GX85 and Olympus E-PL9. The Olympus E-PL9 is clearly the smaller of the two cameras. Its body is 5 mm narrower, 3 mm shorter and 5 mm thinner than the Panasonic GX85.
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.