Hi C.,
I would suggest that you and your wife seek out some counseling on blending families, who can give you some tips on how to make the transition smoother for all of you, especially your step-daughter.
If you could give us some examples of how she is acting bad / not listening I think that you would get some better advice. It sounds like from your other posts that your step-daughter is not handling the blended family very well and is acting out. She is 9. That is what they do.
I don't have a blended family, but my (now) ex b'friend and I went through some counseling and one of the things that was recommended is that you always remember there are 4 relationships in your family of 3:
The relationship you and your wife have with each other.
The relationship you have with your step-daughter
The relationship your wife has with her daughter
The relationship you ALL Have together.
They ALL need equal focus - but you can see that 75% of the "relationships" involve your DAUGHTER. Which means what is going on with her is equally as important as the relationship you are developing with her mom.
How have you bonded with her? How have you worked toward making that relationship easy for her?
How have you supported the relationship between her and her mom as well as how has her mom supported the relationship between you and her daughter?
What activities/family time do you all do together?
When kids are being punished heavily generally it is because there is not enough for the child to do - interacting with family, homework, helping with dinner etc.
See if that will help.