Beijing Airport to Great Wall in March

Hello, I have 9 hours stop over and would like to take my 2 children to the wall, can you advise on the best way to get to the wall. I believe it shuts at 5 we land at 12 so it will be a flying visit, Thanks Claire

On the return journey my children would like to visit the zoo so advise on how yo get their would be great too. Thank you