I would think you can switch him off puppy food now, and keep in mind better quality kibbles are more expensive, but they have more nutrition and you will feed less. I was feeding about 3 cups a day on Blue Buffalo Wilderness and switched to a more pricier Acana and my boy gets 1 cup a day on that to maintain his weight.
"There are two temptations to which people fall prey with dogs. The first is to think that biology counts for everything. The second is to think it counts for nothing"
- Tom Junod
“When you KNOW better you DO better.”
― Maya Angelou