Decreasing the cabin pressure some amount below the ambient pressure at ground level is equivalent to simply pressurizing the ball by that same amount. Even if the plane were fully depressurized at 100,000 feet where the pressure is about 1% that of sea-level, the stress on the walls of the soccer ball would only increase due to a pressure increase of about 15 psi. Doubtful that would pose a problem.

Remember, it is relatively easy to make a flexible spacesuit that can operate in a vacuum.