Yes, DIPPER is a Scrabble word!

Letter values in Scrabble US: D 2, I 1, P 3, P 3, E 1, R 1.

Is it a valid word?

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

a ladle that has a cup with a long handle
a cluster of seven stars in Ursa Minor; at the end of the dipper's handle is Polaris
a group of seven bright stars in the constellation Ursa Major
small North American diving duck; males have bushy head plumage
small stocky diving bird without webbed feet; frequents fast-flowing streams and feeds along the bottom

Also: little dipper, big dipper, charles's wain, bucephela albeola, water ouzel.