Actually science is constantly trying to re-write it’s own rules, so all we ever have are theories, no matter how much evidence there is to back them up (General Theory of Relativity, Quantum Theory, The Grand Unifying Theory).
All science ever really tries to do is present the evidence that is available. In some cases, this means that we can say fairly concrete facts about the universe around us. Other times, if someone looks at all the evidence and comes to a different conclusion to you, I’d be more interested in why they did, then trying to get them to agree with me. Some people may never believe in evolution, and that’s their prerogative.
yes, the scientific meaning of the word “theory” is different to the everyday use of the word. We say that relativity is a theory, for example, but we have a lot of confidence in it. What we mean by theory is that it is a framework for making predictions.
By the way, not only did humans evolve from primates, humans themselves are also classified as primates.