I'd go ahead and take it, besides the fact that it can only help you get into anesthesia school, your current employer should pay for you to take it, and there may be a pay raise for completing it. Just study the questions from a review book and take a few practice tests, you know most of the stuff anyway, its not that bad.
When a school is looking at an application, they will look at the overall picture, if you have a weakness (lower GPA, lower GRE, etc.) think of the CCRN as something to balance that out. More than anything, schools
want to see that you are serious about getting in, even if you dont have a weakness, taking the CCRN, shadowing, taking classes ahead of time, saving up money, etc. shows that you are really committed. I was able to participate in my school's interview process this year and you would be surprised what some people bring to the table (or more specifically, don't bring to the table).