Yes, SHARPIE is a Scrabble word!

Letter values in Scrabble US: S 1, H 4, A 1, R 1, P 3, I 1, E 1.

Is it a valid word?

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

an alert and energetic person
a professional card player who makes a living by cheating at card games
a pen with indelible ink that will write on any surface
a shallow-draft sailboat with a sharp prow, flat bottom, and triangular sail; formerly used along the northern Atlantic coast of the United States

Also: eager beaver, busy bee, live wire, card sharp, card sharper, card shark.