first concert in cleveland for 11 aspiring cellist

Mr. Ma was in St. Louis in February, and our son asked to go. We didn't feel we could afford it at the time, and didn't realize it was so important to us. Neither of his parents are musical, and yet, this child seems to have developed some measurable talent on his own. When I discovered him some weeks later quietly researching if/ when he might again get an opportunity, it became clear that seeing his idol was incredibly important to him. I decided to use frequent flyer points, purchased tickets to Cleveland and am taking him over night so he will have a chance to see a Yo Yo Ma performance. Is there any possibility of getting an autograph either there or in advance? I would be more than happy to purchase a CD that Mr. Ma could autograph.
This will be Andrew's first concert of any type. He is counting down the days to Cleveland with great anticipation.
Thank you for providing this forum.