I can't find the quote, but there's an interview where someone in her circle said she once told him (paraphrasing) "Evolution might be true, but I don't know; it's only a theory..." Apparently Rand had never studied the subject very much, so she didn't want to come out & make a definitive statement on it.
At any rate, anyone who looks at biology & chemistry objectively really has no choice but to accept the basic tenets of the theory of evolution, IMHO.
There are a great many brilliant biologists and chemists who have rejected evolution, at least in any of its present manifestations, because thay all present unsurmountable objectively logical problems.
Here are a couple of simple ones: For the species to evolve, once the animals exist, each new specie requires that both a male and female of the specie come into existense at the same time.
The evolution of a web weaving spider is logically impossible. Until the spider learned how to weave a web, over how many generations, how did it eat?
(The problem with the second question raises is the one of a complete system. The proposal that spiders could have acquired food some other way until web-weaving was evolved ignores that fact that web-weaving is an extremely complex process that must have come into existense, when it did, complete.)
There are billions of similar problems.
By the way, "creationism" is not the only other possibility if evolution turns out to be proveably false, which it is likely to be.