I wouldn't get a fancy wind back tool, many of the universal ones are good enough.
Just remember to take off the fluid reservoir cap and wrap plenty of paper/rags around the area to catch any pushed back fluid over flow.
I haven't done my CX5 rear brakes yet, waiting for some warmer weather.
In the past on other vehicles I have left the piston pad in place and used a G-clamp or lever!
Best of luck with it all