Yes, RUTH is a Scrabble word!

Letter values in Scrabble US: R 1, U 1, T 1, H 4.

Is it a valid word?

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

United States professional baseball player famous for hitting home runs (1895-1948)
the great-grandmother of king David whose story is told in the Book of Ruth in the Old Testament
a feeling of sympathy and sorrow for the misfortunes of others
a book of the Old Testament that tells the story of Ruth who was not an Israelite but who married an Israelite and who stayed with her mother-in-law Naomi after her husband died

Also: babe ruth, george herman ruth, sultan of swat, book of ruth.