Yes, SYNCHRONIC is a Scrabble word!

Letter values in Scrabble US: S 1, Y 4, N 1, C 3, H 4, R 1, O 1, N 1, I 1, C 3.

Is it a valid word?

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

occurring or existing at the same time or having the same period or phase
concerned with phenomena (especially language) at a particular period without considering historical antecedents
(of taxa) occurring in the same period of geological time