I disagree, but it may depend on your definition of "proof". Proof, as a completely self-enclosed and logically perfect statement of reality, does not exist in Science. There are always places where there may be difference between what I expect to be happening and what is reality. I say that I feel keys below my fingertips, but that may all be a delusion created by a divine being to make me think I'm using a keyboard. I cannot in any way prove that it is not true. Science, then, has no interest in such notions of proof.
What science does is create a series of predictions. I felt the key on my finger a moment ago, and I thus predict that when I lower my finger again, I will feel the key again (this is a hypothesis). As long as this remains repeatably observable, it will be the theory that best predicts an outcome. If evidence is introduced that suggests that I will no longer feel a key when I lower my finger, then my theory will have to change. This is as certain as science ever gets.
Common descent is the current theory because it created predictable results. I can look at two fossils and predict that there will be a common ancestor between them, and will often be able to find such a specimen. As long as this remains the case, common descent will be the accepted theory. A creation model, regardless of whether or not it is "true" does not provide me with any such predictive power (at least that anyone has been able to demonstrate), and thus does not rise to the level of scientific hypothesis. As you said, the creation model can be made to "fit" the data, but unless you can make a prediction that can then be demonstrated as wrong, it is not a proper hypothesis.