Yes, SYNECDOCHIC is a Scrabble word!

Letter values in Scrabble US: S 1, Y 4, N 1, E 1, C 3, D 2, O 1, C 3, H 4, I 1, C 3.

Is it a valid word?

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

using the name of a part for that of the whole or the whole for the part; or the special for the general or the general for the special; or the material for the thing made of it