Fujifilm X-T1 IR has a 16.0MP APS-C (23.6 x 15.6 mm ) sized CMOS X-TRANS II sensor and features EXR Processor II processor. On the other hand, Leica M9 has a 18.0MP Full frame (36 x 24 mm ) sized CCD sensor .
Another similarity between these two cameras is that both Leica M9 and Fujifilm X-T1 IR sensors lack anti-alias (Low-Pass) filters. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the X-T1 IR and M9 sensor size comparison.
As seen above, Leica M9 has a 2.3x Larger sensor area than Fujifilm X-T1 IR. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.