September is usually a good month for steelheaders. This month and next, part of the Upper Rogue is fly-angling only; that means regular fly gear or bubble/fly rigs. That also means NO weight on the leader, so leave the split-shot in the bag.
If the river is high, it's a good time to use traditional tactics as well as indicator tactics. A higher level will spread out the fish, and the warmer water will make them more willing to take a swinging fly.
Sometime in mid- to late-September, the Corps of Engineers will drop the output from Lost Creek Dam to around 1,000 cfs. Steelheading gets even better at that time. The water will be cooler and the fish will be more concentrated. Indicator tactics will work best then.
The Rogue is an unusual river, and its steelhead often feed like trout. A favorite meal is caddis pupae. That's why a Big Bird fly dead-drifted near the bottom can be a big producer in fall.
Once the salmon go on their redds (possible late in the month), egg flies will be the best bet.
If the flows drop to around 1,000 cfs, boating can be tricky in some of the areas below Shady Cove. Passage through Rattlesnake Rapids is especially "technical" in low water. If you're new to the river, you might want to take your first boat trip with someone who knows this section.
For more on September tactics and flies, see the Rivers in General forecast