Yes, ROMAN is a Scrabble word!

Letter values in Scrabble US: R 1, O 1, M 3, A 1, N 1.

Is it a valid word?

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

relating to or characteristic of people of Rome
of or relating to or derived from Rome (especially ancient Rome)
characteristic of the modern type that most directly represents the type used in ancient Roman inscriptions
of or relating to or supporting Romanism

Also: roman type, roman letters, roman print, r.c., roman catholic.

Not playable in Scrabble US: ROMANIC, ROMANIST, ROMISH, PAPISTICAL.