Yes, you saved seed will have variations since it is a hybrid. If you grow them out every year and save seeds from one that you like, you will eventually develop a new variety stable variety. It is a gamble with hybrids as to whether or not you will get good offspring, but I can't imagine bad eggplant offspring.
When saving seeds from eggplant, the eggplant need to be over ripe and no longer edible. If you don't let the fruit mature enough, you will not have viable seed.
Remy