Yes, mew is a Scrabble word!
...and is worth 8 points in Scrabble, and 9 points in Words with Friends
mew
Verb
1. Cry like a cat
2. Utter a high-pitched cry, as of seagulls
Noun
1. The sound made by a cat (or any sound resembling this)
2. The common gull of Eurasia and northeastern North America
What Scrabble words can I make with the letters in mew?
2 Letter Words