Yes, HOLDUPS is a Scrabble word!

Letter values in Scrabble US: H 4, O 1, L 1, D 2, U 1, P 3, S 1.

Is it a valid word?

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

robbery at gunpoint
the act of delaying; inactivity resulting in something being put off until a later time

Also: armed robbery.