Evolution is absolutely a fact. The only speculative aspect of its understanding, and exactly why it's still referred to as a theory -- which in scientific terms merely means a confirmed model undergoing further confirmation -- is the exact nature of every detail in the process. Scientific models are assembled based on observed and testable facts. Those are each real, testable for reality, hold-in-you-hand-proof facts, none of them speculation or pseudo-facts, but actual proof one way or the other. It just so happens that every bit of new information about evolution discovered confirms the theory. What makes scientific theory more than just a guess is that each new bit of information gives us more material for testing and more mortar for assembling an ever more complete picture. One part of that assembly process is using information already in hand to make predictions about further developments. It is this predictive aspect of the process that qualifies the whole process as a theory. These predictions are tested for either confirmation or proof as false. The more we discover, the more accurate the scientific fact of evolution becomes in every detail.
Creationism is built on logical fallacies, most notably the "god of the gaps" leap-of-faith which says, "I don't know, therefore God." The therefore God part inserts a wide array of myths, legends, hearsay, old wives tales and superstition. Nowhere in Creationism is there an actual theory, nor is there anything to test or with which to make predictions about which to test. Creationism is, at best, philosophy, and does not even begin to approach the definition of science. That is why Creationism cannot pass muster in courts of law. Creationism is not science and does not qualify for a place in any manner of science class.