Yes, ANYHOW is a Scrabble word!

Letter values in Scrabble US: A 1, N 1, Y 4, H 4, O 1, W 4.

Is it a valid word?

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

used to indicate that a statement explains or supports a previous statement; anyhow, they're quiet"; anyway, it's gone"; in any case, there was a brief scuffle"
in any way whatsoever

Also: in any case, at any rate, in any event.