Below you can see the front-view size comparison of the Olympus E-PL9 and Panasonic S1R. The Olympus E-PL9 is clearly the smaller of the two cameras. Its body is 32mm narrower, 42 mm shorter and 58 mm thinner than the Panasonic S1R.
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.