In brief, my answer would be yes research-level questions on the subject Mathematics Education are, or at least should be (if the perception is that this is not so), allowed on MO.

However, while not being a firm in this subject myself, I would say that your question is not a research-level question on Mathematics Education. Rather, you seem to *want to do a survey* that is, or could be, part of some research-activity in this field. 

This does not seem like a good fit for MO, not unlike it does not feel like a good fit for MO to ask people to proof-read preprints or other things that are more crowd-sourcing some legwork of research, as opposed to asking a precise question. 

For example, had you asked about existing research-papers on this subject or existing data on it, this would be a question more in the spirit of the general MO-model and more generally SE Q&A sites.

Put differently, I think research-questions on Mathematics Education should be allowed, carrying out surveys as part of Mathematics Education research should not be allowed, and this goes, possibly with rare  exception, for any other survey- or polling-type questions.