Yes, EMBRYO is a Scrabble word!

Letter values in Scrabble US: E 1, M 3, B 3, R 1, Y 4, O 1.

Is it a valid word?

EMBRYO is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

(botany) a minute rudimentary plant contained within a seed or an archegonium
an animal organism in the early stages of growth and differentiation that in higher forms merge into fetal stages but in lower forms terminate in commencement of larval life

Also: fertilized egg.