Most people don't at hand know who who Adi Shankara is. Nor are they familiar with the arguments in favour of considering someone who is perhaps over revered as influential in Hindu philosophy as crypto Buddhist. That would require familiarity with both Hinduism, Buddhism and any overlap between them with respect to their development. You might not get much response on that basis without leaving anything to chew on.
Yeah, I'm probably one of the few on here who even knows who he is without looking him up.
I vote No. While he might have had Buddhist influence, he's definitely Hindu. Buddhism rejects or doesn't concern itself with the existence of an eternal individual soul (atman) and a God/Cosmic Energy Force (brahman). That's a main point of Buddhism. But the existence of atman/brahman (and of atman=brahman) are a main point of Hinduism, and of Adi Shankara's beliefs/philosophy.