According to Fujifilm, the XF 18-55 at 55 mm has a maximum magnification of 1:6.67, while the XF 90 has a maximum magnification of 1:5. This means, when both lenses are at their close focus distance, the XF 90 should see a slightly tighter crop. The image area in the plane of focus of the XF 18-55 at 55 mm should be around 16.7 cm x 11.1 cm, while the image area of the XF 90 should be ~ 12.5 cm x 8.4 cm. I've added those frame lines to your image:
But please also consider that your depth of field gets smaller as your magnification increases. So even if you buy a lens with better magnification and brighter aperture, you might still end up closing the aperture down to get the whole head in focus. I've added some pictures I took with the XF 80 f/2.8 wide open at f/2.8: (the last bird might even be a pigeon, but you'll know better than me)
You can see that at f/2.8, the feathers at the back of the heads as well as the beaks are already very unsharp and out of focus in the portrait images while the eye is sharp. Even with less magnification as seen in the last picture, you can run into those problems.