Yes, WARHEADS is a Scrabble word!

Letter values in Scrabble US: W 4, A 1, R 1, H 4, E 1, A 1, D 2, S 1.

Is it a valid word?

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

the front part of a guided missile or rocket or torpedo that carries the nuclear or explosive charge or the chemical or biological agents