Yes, hex is in the scrabble dictionary.

Is this word OK for scrabble?

"OK" is now OK to play in a game of Scrabble. The two-letter word is one of 300 new additions to the latest version of the Official Scrabble Players Dictionary, which Merriam-Webster released on Monday. ... Not all Scrabble players are OK with OK, however, especially at the game's highest levels.

Is HEXO a word?

hexo is an acceptable dictionary word for games like scrabble, words with friends, crossword, etc. The word 'hexo' is made up of 4 letters.