Yes, kat is a Scrabble word!
...and is worth 7 points in Scrabble, and 7 points in Words with Friends
kat
Noun
1. The leaves of the shrub Catha edulis which are chewed like tobacco or used to make tea; has the effect of a euphoric stimulant
What Scrabble words can I make with the letters in kat?
2 Letter Words