Yes, PETERS is a Scrabble word!

Letter values in Scrabble US: P 3, E 1, T 1, E 1, R 1, S 1.

Is it a valid word?

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

disciple of Jesus and leader of the Apostles; regarded by Catholics as the vicar of Christ on earth and first Pope
obscene terms for penis

Also: simon peter, saint peter, st. peter, saint peter the apostle, st. peter the apostle.