Hi Jennifer,
Actually you don't want him to play. Sometimes activity lowers blood glucose levels.
I am guessing you will be okay, but let's just watch and make sure.
So - tomorrow. If you get any number around 200, I would wait 30 minutes and test again. You want to make sure it is headed up. Even if you get a higher number than usual, which you could since he had high carb and dry food tonight, if I were you, I would be cautious. I would give one unit, or even .5.
When are you planning to switch to Lantus?