Yes, ACTUALLY is a Scrabble word!

Letter values in Scrabble US: A 1, C 3, T 1, U 1, A 1, L 1, L 1, Y 4.

Is it a valid word?

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

in actual fact
used to imply that one would expect the fact to be the opposite of that stated; surprisingly
at the present moment
as a sentence modifier to add slight emphasis

Also: in reality.