Both begin with a conclusion. Darwinistic Materialism assumes purely naturalistic causes to explain the unobservable, unrepeatable past. Creation Science assumes that Genesis is a true historical account of the unobservable, unrepeatable past. The question is, which approach explains the remnants of the past better. To my mind, Creation Science is the far better explanation.
There are reasonable assumptions and there are unreasonable assumptions. Naturalism (I’m not certain what you mean by “Darwinistic Materialism”) is a reasonable assumption. That a certain creation myth must be the true account of the origins of man, life, and the universe is an unreasonable assumption.
What’s more, science does not seek to prove or show evidence that naturalism is correct or true. Whereas christian creationism begins with it’s own conclusion, that a certain ancient creation myth is true, which it then it seeks to prove.