Yes, SYCAMORES is a Scrabble word!

Letter values in Scrabble US: S 1, Y 4, C 3, A 1, M 3, O 1, R 1, E 1, S 1.

Is it a valid word?

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

variably colored and sometimes variegated hard tough elastic wood of a sycamore tree
any of several trees of the genus Platanus having thin pale bark that scales off in small plates and lobed leaves and ball-shaped heads of fruits
Eurasian maple tree with pale grey bark that peels in flakes like that of a sycamore tree; leaves with five ovate lobes yellow in autumn
thick-branched wide-spreading tree of Africa and adjacent southwestern Asia often buttressed with branches rising from near the ground; produces cluster of edible but inferior figs on short leafless twigs; the biblical sycamore

Also: plane tree, great maple, scottish maple, acer pseudoplatanus, sycamore fig, mulberry fig, ficus sycomorus.