Yes, RACKED is a Scrabble word!

Letter values in Scrabble US: R 1, A 1, C 3, K 5, E 1, D 2.

Is it a valid word?

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

go at a rack
stretch to the limits
put on a rack and pinion
obtain by coercion or intimidation
run before a gale
fly in high wind
draw off from the lees
torment emotionally or mentally
work on a rack
seize together, as of parallel ropes of a tackle in order to prevent running through the block
torture on the rack

Also: single-foot.