Yes, REAL is a Scrabble word!

Letter values in Scrabble US: R 1, E 1, A 1, L 1.

Is it a valid word?

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

being or occurring in fact or actuality; having verified existence; not illusory; not ghosts"
no less than what is stated; worthy of the name
not to be taken lightly
capable of being treated as fact
being or reflecting the essential or genuine character of something
of, relating to, or representing an amount that is corrected for inflation
having substance or capable of being treated as fact; not imaginary
(of property) fixed or immovable
coinciding with reality

used as intensifiers; `real' is sometimes used informally for `really'; `rattling' is informal

Also: real number.