Yes, OBJECTION is a Scrabble word!

Letter values in Scrabble US: O 1, B 3, J 8, E 1, C 3, T 1, I 1, O 1, N 1.

Is it a valid word?

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

the act of expressing earnest opposition or protest
the speech act of objecting
the act of protesting; a public (often organized) manifestation of dissent
(law) a procedure whereby a party to a suit says that a particular line of questioning or a particular witness or a piece of evidence or other matter is improper and should not be continued and asks the court to rule on its impropriety or illegality