Yes, HERETOFORE is a Scrabble word!

Letter values in Scrabble US: H 4, E 1, R 1, E 1, T 1, O 1, F 4, O 1, R 1, E 1.

Is it a valid word?

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

used in negative statement to describe a situation that has existed up to this point or up to the present time

Also: so far, thus far, up to now, as yet, til now, until now.