Candidacy is usually referred to the qualification required for a candidate to apply for a specific post.
However, does “Candidacy ” sometimes refer to the person as well? Can I say “Candidacy for this open position”? Is that acceptable for a native speaker?
Candidacy or Candidature is a noun and it means the whole process of applying for (a position).
You could say Candidacy for this open position but it would not be referring to a person. The proper form would be:
His candidacy for this open position was surprising to all.