This video is from his practice run-through right before the concert started. During his actual performance, he was slightly more distracted and even stopped at one point and said to his cousin Austin in the audience, "Sing it with me Austin!". Since he has grown up seeing his Dad on stage his whole life, he doesn't realize there is anything to get nervous about! But there were already about 30 people in the audience when he did his practice run.
Here he is, playing Happy Birthday and You Belong With Me by Taylor Swift. I love how he looks up a couple times during the songs just to check out who is watching him!