Yes, CYBERPUNK is a Scrabble word!

Letter values in Scrabble US: C 3, Y 4, B 3, E 1, R 1, P 3, U 1, N 1, K 5.

Is it a valid word?

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

a programmer who breaks into computer systems in order to steal or change or destroy information as a form of cyber-terrorism
a writer of science fiction set in a lawless subculture of an oppressive society dominated by computer technology
a genre of fast-paced science fiction involving oppressive futuristic computerized societies

Also: cyber-terrorist.