Yes, OCCLUSIONS is a Scrabble word!

Letter values in Scrabble US: O 1, C 3, C 3, L 1, U 1, S 1, I 1, O 1, N 1, S 1.

Is it a valid word?

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

closure or blockage (as of a blood vessel)
(meteorology) a composite front when colder air surrounds a mass of warm air and forces it aloft
(dentistry) the normal spatial relation of the teeth when the jaws are closed
an obstruction in a pipe or tube
the act of blocking

Also: occluded front.