Yes, OFFENSES is a Scrabble word!

Letter values in Scrabble US: O 1, F 4, F 4, E 1, N 1, S 1, E 1, S 1.

Is it a valid word?

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

a lack of politeness; a failure to show regard for others; wounding the feelings or others
a feeling of anger caused by being offended
(criminal law) an act punishable by law; usually considered an evil act
the team that has the ball (or puck) and is trying to score
the action of attacking an enemy

Also: offensive activity, criminal offense, criminal offence, law-breaking.