Can a postdoc apply for a standard NSF grant as a PI?
I work in theoretical mathematics.  I have known several postdocs who have received individual NSF research grants.  In fact, I am co-PI on a NSF Research Training Grant which has supported several postdocs, and we have required these postdocs to apply for individual grant support in every year of the job.

Having said that: all NSF grants are of course (i) a lot of work to apply for and (ii) quite competitive to receive, so before taking the time to apply for one I would want to get additional reassurance that not only is it legal for postdocs to apply for your particular kind of NSF grant (as it almost certainly is) but moreover that those who are reviewing the grants view it as reasonable that a postdoc might get such a grant, or -- better -- that some postdocs in your field have actually gotten such grants.

My advice for this is twofold:


  Do some research on this yourself.


Who gets what NSF grant is public information.  Whether the grantholder is a postdoc is something you will probably have to do further web research to find out, but it should be doable.  Try it!


  Ask followup questions to your program officer.


As you describe it, you sent one message to your program officer and got a response, but the response was based on a bit of misunderstanding of your situation.  Okay, then try again.  In your second (and third..., if necessary) try, you can ask additional questions based on what I wrote above: i.e., not just whether it's legal, but how does it work out in practice?  By the way, it is (a big part of) the job of NSF program officers to answer such questions.  As long as you are polite and respectful, you can ask her as many questions as you have...and I encourage you to do so.