Yes, AGITATE is a Scrabble word!

Letter values in Scrabble US: A 1, G 2, I 1, T 1, A 1, T 1, E 1.

Is it a valid word?

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

try to stir up public opinion
cause to be agitated, excited, or roused
exert oneself continuously, vigorously, or obtrusively to gain an end or engage in a crusade for a certain cause or person; be an advocate for
move very slightly
move or cause to move back and forth
change the arrangement or position of

Also: stir up, turn on, charge up, shake up, raise up.