Yes, EARTHWORM is a Scrabble word!

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

Is it a valid word?

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

terrestrial worm that burrows into and helps aerate soil; often surfaces when the ground is cool or wet; used as bait by anglers

Also: fishing worm, dew worm, red worm.

Not playable in Scrabble US: NIGHTCRAWLER.