If Stanford, or any other college, considered AP exams in lieu of Subject Tests, they would say so. Stanford does not say so, so one should assume they don’t regardless of one’s personal opinions. So again, the question comes down to “Will the lack of Subject Tests hurt?” It might. or it might not.
There’s a whole thread on the topic.
http://talk.collegeconfidential.com/college-admissions/2027962-sat-subject-tests-are-not-truly-optional-for-middle-upper-middle-class-applicants-at-elite-colleges-p1.html