No, actually, creationists do *not* believe in a rational ordered universe.
I am a physicist. I don't know what all the laws of physics are, but I believe that there *are* some inviolate laws of physics which apply uniformly throughout all that is. So far as we can tell, this is true: spectral lines in distant stars are the same as they are here, to very high precision, indicating that atomic and nuclear physics are the same. Electrodynamics and such work the same way inside stars as it does in all conditions we've found on Earth.
I suppose you could be a creationist and believe in a deistic universe, where a god chose the laws of physics and then wound up his universe and let it go. But modern creationists do not believe this: they are overwhelmingly Christian, and believe in such things as a god that actively intervenes on this little planet by making virgins pregnant, people turn into pillars of salt -- in general, they believe in miracles, even small ones like altering the genetic makeup of a species. This is the very opposite of a rational ordered universe: all these things, all these miracles, are inherently disordered, since they entail violations of the laws of physics by an entity outside of them. "F=ma, except when god says otherwise" is not a sound basis for a rational theory of the universe.
They do not believe in a completely ordered and repeatable existence. That is, they do not make the (actually inherently risky) assumption that just because we've seen lots of things behave as if they are ordered and repeatable, all things must always be so.
Consider a man in a room who asks his colleague (outside) to bring in any cats he finds that are black so he can count them. If a cat isn't black, don't bring it in -- maybe it'll be black later or maybe it's black in some way I can't see yet, so we'll reserve judgment on it and not include it as any form of evidence either way. Naturally, the man in the room can only see an endless stream of black cats, and might (wrongly) be tempted to think that is ever-increasing evidence that all cats are black. Unfortunately, that is the position of a man who believes that because we've found more and more orderliness and repeatability in the universe, existence must all be orderly and repeatable.
Those who believe in any form of divine action (including but not limited to creationists) are actually rather more rational in their conclusion in this regard: "Wow, there's a lot of black cats, and we can probably find lots more, but I'm not going to insist they all must be". Separate sources of evidence then give them reason to believe that God is an example of something that is real but not mechanistically repeatable.
Interestingly, a lot of the early impetus for science -- the notion that the universe would be orderly at all -- came from the religiously-derived belief that it would be ordered because it would obey laws laid down by God for it. That derivation, of course, does not exclude divine action nor does it have your slightly obsessive "all or nothing -- either it's completely ordered always or otherwise it's a totally irrational model" mantra.
Funny anecode/aside, but "F=ma except when god says otherwise" is not only a rational model but is precisely what is modelled in almost every simulation -- almost every simulation I have seen or written has allowed its author to pause it, change a variable, and then set it going again.