Yes, DABBLER is a Scrabble word!

Letter values in Scrabble US: D 2, A 1, B 3, B 3, L 1, E 1, R 1.

Is it a valid word?

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

an amateur who engages in an activity without serious intentions and who pretends to have knowledge
any of numerous shallow-water ducks that feed by upending and dabbling

Also: dabbling duck.