This is all wrong! The ball is red because of its reflective properties. Physicists can confirm that by examining the spectrum of incident radiation and comparing it to the reflected radiation, which is within the range of radiation that our neural systems recognize as red, a word we have tacitly agreed to denote that range of radiation.
There are a number of objective ways we can confirm the spherical shape of the ball. A sphere is a precisely described mathematical object. We have tacitly agreed to use that word when objects approximate that shape.
When we say, "red ball," we are describing that objective reality.
It seems the only non-intuitive aspect of all this is your own lack of intuition.
The reflective properties of the ball do not in any way involve redness.
Redness is produced in the brain, at a time after the light reflected from the ball is distant from the retina, and it is produced in areas of the brain also distant from the retina.
Of course, in everyday parlance, it's perfectly fine to talk about redness as being inherent in the object reflecting the light, but it's not fine in this context because it will cause critical mistakes.
Keep in mind that when we examine a spectrum we are necessarily examining our brain's response to light, not the light itself. The inherent properties of light are things like speed, wavelength, and frequency. But we don't experience any of these.
If we knew how to build conscious brains, we could just as well build a brain that responded to light with various scents, or degrees of nausea, or anything else. The fact that our brains respond with color is simply a historical accident of evolution. But it makes no sense to say that our brains' reactions are somehow inherent properties of light. No doubt, other animals have varying color responses from humans, so in that case, which color response are you going to assign to the light?
As for the shape, that's the flip side.
We do not experience the actual shape of anything.
In fact, we live in a world of impossible geometry.
It is literally impossible for us to build a 3-D model of the spatial world which our conscious minds conjure up. That's because everywhere you look, parallel lines converge into a vanishing point. The world we experience is a set of nested spheres, each one smaller than the ones it contains, with the outermost shell being not a sphere at all but a point!
So no, the ball isn't red, and we don't consciously perceive its actual shape.