Yes, LUFFA is a Scrabble word!

Letter values in Scrabble US: L 1, U 1, F 4, F 4, A 1.

Is it a valid word?

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

the dried fibrous part of the fruit of a plant of the genus Luffa; used as a washing sponge or strainer
any of several tropical annual climbers having large yellow flowers and edible young fruits; grown commercially for the mature fruit's dried fibrous interior that is used as a sponge

Also: loufah sponge, dishcloth gourd, sponge gourd, rag gourd, strainer vine.