You should have got 2 kittens if you are out all day, then you would not need to worry about her being alone. Kittens get lonely too! lol.
Seriously though, you should feed her what she is used to, and then if you are going to change her food , do it gradually by mixing in a little of the new food , and increasing the amounts until she is eating the new food only. Dont be suprised if she gets the runs if you are going to change her food, this often happens. My cats only eat dry food, but they also drink plenty of water. They dont have meal times, I just keep the dishes topped up and they can eat whenever they like. Please dont make the classic mistake of giving her lots of variety. Cats are not like us, they do not need it , and you will end up with a fussy eater and have to throw food away. Good luck.