Sounds like someone needs a lesson in the philosophy of science, in particular falsifiability (its ok, I’ll wait while you go look it up on wikipedia, while your at it, go look up Karl Popper he'll come up later).
Unfortunately, I can’t do this lesson justice without a thick Finnish accent (my Lecturer in Sociology of Science and Scientific Ethics was Finnish), but I’ll try:
The two most fundamental aspects of any scientific theory are as follows:
It must predict an observable/testable phenomenon
And it must be capable of being proven False.
The first aspect, (testability) is necessary for a theory to be useful, enforces specificity (IE a theory must predict a single and repeatable outcome), and is also necessary for the second aspect, (falsifiability). The necessity for falsifiability is simple; it is very easy to find evidence supporting any theory or hypothesis, regardless of it’s correctness. If however, a theory is correct, it will not have any evidence to the contrary. Therefore, instead of wasting our time looking for supporting evidence, one should always try to look for contradicting evidence, and when you have failed to find contradicting evidence, then you can say that you have failed to disprove the theory.
Furthermore, the strength of a theory is determined by the strength of the predictions it makes, and the strength of the evidence to the contrary.
Time to fall back to Karl Popper’s famous analogy. Lets say you have a scientific theory about Swans: You theory is that all swans are white. This checks out with both criteria for a scientific theory, it is testable (or at least observable, find a swan and observe its color), and is also falsifiable (find a swan that isn’t white). Now then, you can sit in your backyard all day and point at white swans, and say “SEE, a white swan, that supports my theory!” But yet there could very well be a black swan living in a lake just down the road, or somewhere else in the world, which you have never seen. Your theory is weak because your evidence that there are no non-white ducks is weak. This does not mean your theory is necessarily wrong, just that it is easy to disprove. If however you scour the face of the earth looking for non-while swans (documenting as you go, of course) and still fail to find any non-white swans, then your theory is strong, and difficult to disprove).
In terms of evolution, it is most defiantly a theory. It predicts observable phenomenon (that physiological changes occurred in organisms in the past due to external stimulus), and is falsifiable (Observe evidence that these organisms did not undergo physiological changes, or that these changes occurred instantly). Evolution, like every other theory, cannot be proven, Ever. It can only ever be disproved, or fail to be disproved.
Creation is also a theory, predicting that life appeared in its present form (I’m simplifying things here just a little). And it’s also falsifiable (prove that organisms have changed over time) So Creation is also a valid theory. Now, if you say that God planted evidence that organisms changed over time, when they didn’t then Creation ceases to be a theory because it also ceases to be testable or falsifiable, it instead becomes a belief.
The existence of God is NOT a theory (well, most often not). In order for the existence of God to be a theory, his existence must be observable and/or testable, and the absence of god must also be observable and/or testable. Many people will argue that God is unknowable/unquantifiable, therefore unable to be tested. This makes the existence of God a Belief, not a theory.
So far, there is not final substantial evidence to disprove Evolution (that is to say, there are no Black swans), there is evidence we don’t really know what to do with yet (Dirty swans whose color is hard to determine). Until someone can flat out disprove evolution, it’s still a theory, and based on the lack of strong disproving evidence, most scientists will agree it’s still a strong theory.
I’ve spoken my peace. Now:
GOOD SCIENCE PREVAILS!

"Well, if I am not drunk, I am mad, but I trust I can behave like a gentleman in either
condition."... G. K. Chesterton
“questions are a burden to others; answers a prison for oneself”