I developed a new appreciation for the Narrows on my last trip. The water was a little low so I settled on a different route than I'd planned and discovered a nice little out of the way and rather well protected island site I never knew existed. I normally just blow through that area because on my first (or second?) trip, we spent our entire second week in the Narrows and I returned to poke around and get to know it once or twice early on.
There are some interesting areas in there I've almost forgotten. That glacier scraped granite w/ quartz, what, intrusions, some great long vistas, shallow weedy areas and the magic rock! (A humongus erratic split in two you can walk into.) The nice thing is that, for staying on Pickerel, you're really never wind-bound like you could be in most other areas.
Stanton Bay is always pretty good fishing. I'm not sure why. The larger body of Pickerel is often hit and miss besides the usual laker hangouts.
If it's a first trip for him, just the portages between your put-in and take-out would give a 9 yr old a fair taste. I wouldn't take a kid down to Bud and back and then out Nym in 5 days. Rawn, maybe, if he likes to paddle. The fishing is more predictable on smaller lakes. Less places to hide??

Think of the narrows as a smaller lake.
Spend at least one night on the big lake though. If you hit it right, dusk or dawn can be a truly unforgettable sight he may not soon forget.