Yes, STRAWWORM is a Scrabble word!

Letter values in Scrabble US: S 1, T 1, R 1, A 1, W 4, W 4, O 1, R 1, M 3.

Is it a valid word?

STRAWWORM is a valid word in the official Scrabble dictionary (US) and the UK Scrabble Dictionary, but not in Words with Friends (ENABLE).

larva of the caddis fly; constructs a case of silk covered with sand or plant debris
larva of chalcid flies injurious to the straw of wheat and other grains