If I was asked by an eight-year-old how that child could know God, there would be a couple of layers to my answer. The first is knowing about God. This is really important. We want to go beyond knowing about God, but it all starts with knowing about God. And we need to know about, and we need to know the God who is.
Well, how do I do that? Only through His Word. If you don't start somewhere else, you end up with a God of your imagination. You end up with a God who very, very rarely contradicts you. He's always happy with you no matter what patterns of sin persist in your life and never contradicts those and never asks you to turn away from those.
Many people who say they know about God don't know about the God of the Bible at all. Who confronts us in our sin and then offers us freedom from the sin. So I would say to that eight-year-old, the first thing that's important is to know the God of the Bible. Know the God who has revealed himself to us in the Bible. And then the second layer to that would be he can be known, wants to be known, must be known in more than an academic sense.
In other words, we don't read our Bibles, learn about the revelation of God in the Bibles like we would study a math book. It's more, I think we should be thinking of the Bible as a love letter, as a communication of intimacy, of friendship, and not just in an academic sense.