Welcome!
He’ll probably be about the size of his parents, maybe more, maybe less, unless there is a large breed somewhere in his background.
Kaytee food is okay, but it’s not the best. Oxbow food is very good and it’s sold at PetSmart or you can order it online on this site or other places. If he is a baby bunny, then he’ll need alfalfa food until he’s about 7 months old, and then he needs to be switched to timothy pellets. He is going to need hay everyday, and once he gets settled, you can start to introduce greens to his diet. Eventually he will need at least 2 cups of veggies per day.
The smallest cage he can be in is 2 x 4 feet. Larger is better. I’d recommend you skip the cage and get a puppy exercise pen which is 4 x 4 feet.
Boys can be neutered at about 3-4 months, this is when their testicles descend.
Willow toys are my buns’ favorites. They are available on this site and they are very inexpensive. Petstore toys are not very good for bunnies and they tend to be ignored. You can also do cardboard boxes for hidey houses and phonebooks (with glossy covers ripped off) for shredding and digging.
This is just the very brief rundown… For more specific info, check out the House Rabbit Society http://www.rabbit.org/
And there are info pages at the top of this site under “Bunny Info”