Yes, SANDBAGGED is a Scrabble word!

Letter values in Scrabble US: S 1, A 1, N 1, D 2, B 3, A 1, G 2, G 2, E 1, D 2.

Is it a valid word?

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

treat harshly or unfairly
compel by coercion, threats, or crude means
hit something or somebody as if with a sandbag
downplay one's ability (towards others) in a game in order to deceive, as in gambling
protect or strengthen with sandbags; stop up