Notice the consumer price index has flattened since June (i.e. very little inflation). Also notice the levels from a year ago, which the current CPI reading is being measured against.
The takeaway: Even if inflation flat-lined from here, it would be many months before the year-over-year inflation number dropped materially. In fact, if CPI flat-lined, it would be February before the headline number would drop below 5%.
But if the Fed is executing policy to slow the rate-of-change in prices, the Fed should be concerned about the recent rate-of-change, not the change relative to last year's price. The recent data should give them information on whether or not their policies are working.
With that, if we look at the monthly change in prices, over the past three months, it has been tame. July was 0%. August was 0.1%. And September was 0.4%. That's a three-month average of 0.2%.
If you woke the Fed up today, and told them inflation was running at a 0.2% three-month average (annualized at less than 2.5%), they would be doing nothing with interest rates.