Yes, REALIZED is a Scrabble word!

Letter values in Scrabble US: R 1, E 1, A 1, L 1, I 1, Z 10, E 1, D 2.

Is it a valid word?

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

be fully aware or cognizant of
perceive (an idea or situation) mentally
make real or concrete; give reality or substance to
earn on some commercial or business transaction; earn as salary or wages
convert into cash; of goods and property
expand or complete (a part in a piece of baroque music) by supplying the harmonies indicated in the figured bass

Also: take in, pull in, bring in.

Not playable in Scrabble US: AGNISE, ACTUALISE.