I've had good luck the last week of September for several years. The weather is still pretty warm and I've found fish two ways.
East of Kellys (3-5 miles, 50 ft depth) look on your sonar for bait balls with walleyes beneath. I troll dipsy's and spoons just above the walleye marks. Closer to Kellys (35-40 fow) you can't see them on the sonar but fish have been right on the bottom. Drift fish with crawler harnesses or troll baits right on the bottom.
Good Luck!
CaptKen
"Lucky Luna" Channel 68
SeaRay Amberjack 290
Twin Mag 350s/v-drives
Simrad NSX 12
Simrad AP44 Autopilot
FishHawk X2