Yes, CANONS is a Scrabble word!

Letter values in Scrabble US: C 3, A 1, N 1, O 1, N 1, S 1.

Is it a valid word?

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

a rule or especially body of rules or principles generally established as valid and fundamental in a field or art or philosophy
a priest who is a member of a cathedral chapter
a ravine formed by a river in an area with little rainfall
a contrapuntal piece of music in which a melody in one part is imitated exactly in other parts
a complete list of saints that have been recognized by the Roman Catholic Church
a collection of books accepted as holy scripture especially the books of the Bible recognized by any Christian church as genuine and inspired