Yes, vary is a Scrabble word!
...and is worth 10 points in Scrabble, and 10 points in Words with Friends
vary
Verb
1. Become different in some particular way, without permanently losing one's or its former characteristics or essence
2. Be at variance with; be out of line with
3. Be subject to change in accordance with a variable
4. Make something more diverse and varied
What Scrabble words can I make with the letters in vary?
3 Letter Words
2 Letter Words