Yes, SYNOPTIC is a Scrabble word!

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

Is it a valid word?

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

presenting a summary or general view of a whole
presenting or taking the same point of view; used especially with regard to the first three gospels of the New Testament