Yes, KNITTINGS is a Scrabble word!

Letter values in Scrabble US: K 5, N 1, I 1, T 1, T 1, I 1, N 1, G 2, S 1.

Is it a valid word?

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

needlework created by interlacing yarn in a series of connected loops using straight eyeless needles or by machine
creating knitted wear

Not playable in Scrabble US: KNITWORK.