Too Much Time on His Paws?

Whoever first wrote that Bichon Frise Puppies are energetic should be awarded something for the art of understatement. This little rascal of mine has a level of energy that is nothing short of overwhelming and if I don't keep a constant eye on him, his curious nature takes that energy and turns it into trouble!
Today for instance, I had to go downstairs to change the laundry batches. I was gone maybe 34 minutes and when I came back, my baby was no where to be found. Where was he? Oh he was UNDER the sofa gnawing on the wooden supports.
I understand he may be teething, but that's what the Dynabones are for I was a nervous wreck while I was searching for him. Some experts say that exercise is the answer, but I also read that too much exercise before he's a year old can lead to long term problems as he ages.
Since his breed has some tendencies toward dysplasia already, the vet has given me the advise to temper exercise with just play time. Baby and I take regular walks and I let him play in the wading pool frequently. However, do I really have to count chewing on the sofa as play time?