Kit
not short for anything. The advantages are:
a. the boys will like it.
b. the girls will soon accept it.
c. the teachers will get used to it.
d. combining it with a middle name makes it more appealing, especially when paired with other gender-benders, i.e., Kit Morgan, Kit Tyler, Kit Cassidy, or a very feminine version would be Kit Delicata. (See Delicata)