One of the issues with food today isn't the fact that we can't feed 9b people, it's the fact that we produce enough food to feed 15b only to feed it to cattle and then eat its meat. If we gave up on eating meat every meal to eat it once a week or even not at all we would have so much more food.
By the way if you like technology/gaming/personal development I'm writing about it, you might like it :)