Answer
The ball would pass through more easily.
Work Step by Step
When the metal ring is heated, it expands uniformly, as though a 3D picture of it were enlarged on a magical photocopier. The thickness, outer and inner circumference all expand. So the ball that could pass through a cool ring will easily pass through the expanded hole in the hot ring.
Another way to think about this is that the hole will expand precisely as much as a pancake-shaped plug of the same metal that filled the hole.
