Yes, KIWIS is a Scrabble word!

Letter values in Scrabble US: K 5, I 1, W 4, I 1, S 1.

Is it a valid word?

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

climbing vine native to China; cultivated in New Zealand for its fuzzy edible fruit with green meat
a native or inhabitant of New Zealand
fuzzy brown egg-shaped fruit with slightly tart green flesh
nocturnal flightless bird of New Zealand having a long neck and stout legs; only surviving representative of the order Apterygiformes

Also: chinese gooseberry, kiwi vine, actinidia chinensis, actinidia deliciosa, new zealander, kiwi fruit.