Yes, OBSTRUCTION is a Scrabble word!

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

Is it a valid word?

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

any structure that makes progress difficult
the physical condition of blocking or filling a passage with an obstruction
something immaterial that stands in the way and must be circumvented or surmounted
the act of obstructing
getting in someone's way

Not playable in Scrabble US: OBSTRUCTER.