Is the evolution vs. creation debate a significant issue among grad students? Yes. No.
By the time someone has arrived in graduate school he/she has generally come to a conclusion regarding what to believe about evolution. Those studying biology at that level usually decide that evolution is the way God formed the world into being. Whatever struggle they might have had on the issue of creation or evolution has generally been resolved. Thus, no, it is not really an issue.
Those outside of the sciences may or may not have come to a conclusion on how much evolution was (or wasn’t) involved with the formation of the world. The lack of conclusion is in itself an indication that for him/her the debate is not really a big issue (balancing and finishing grad school and living out one’s faith being much bigger issues).
However, it does, yes, become an issue when other scientists hear Christians arguing (with mediocre science) that the world had to be created less than 10,000 years ago. Christianity is then mocked and potentially rejected. How does a Christian scientist respond well to how Christians present themselves and/or are perceived?
And yes, it also becomes an issue when one is told that Christianity and evolution are completely incompatible: choose between either Christianity or evolution. Or one is told it is a sin to believe that evolution happened. (Likewise, it is problematic to treat as incompetent (idiots) those who have difficulties believing God formed the world via evolution).
Several examples of these last two – a struggle of a Christian within science – can be seen here: Christian women in stem are a vulnerable minority