Yes, WISDOM is a Scrabble word!

Letter values in Scrabble US: W 4, I 1, S 1, D 2, O 1, M 3.

Is it a valid word?

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

accumulated knowledge or erudition or enlightenment
the trait of utilizing knowledge and experience with common sense and insight
ability to apply knowledge or experience or understanding or common sense and insight
the quality of being prudent and sensible
an Apocryphal book consisting mainly of a meditation on wisdom; although ascribed to Solomon it was probably written in the first century BC

Also: wisdom of solomon.