A09 on the sensor means its the correct one. Do you have an engine light on? Does it stumble in lean burn? What mileage are you getting?
I'm happy to say that I don't either have an engine light, nor does it stumble at all. However what I will say, is that the gas mileage is not up to VX standards. What I have noticed though, is that the idle fluctuates and pulses little whenever I sit at a light. It wasn't doing that when I first got it.
I bought the NGK 24300 and it works great, passed smog and continues to get in the high 40s for MPG. The prices vary a lot depending where you get one. O'Rielly wants $400, but there is one on Ebay for $100
It sounds like you have a different issue. Fluctuating idle is a common problem and the fix can elude some really good mechanics. Look at cleaning your IACV and taking off your MAP sensor, cleaning it and looking for carbon deposits around it. If you don't know how to do it, look on YouTube, there are some really good tutorials on this.