Need help, Why is she lying?

My step daughter (9) and I have been struggling for the last 4 months. She has beeen lying about a lot of things, she throws fits on me and her dad everytime she made to do something that she doesn't want too. While I know that some of this is pretty normal, I am concern that this could be something deeper. As some of you may know of our past problem. I am concerened that the lying isn't safe, we have discussed this with her about being honest. Her therapy ended and they said she was fine awhile ago but is she? Is this her trying to just push just to get her way? I mean she was my shadow before summer, and she can back from spending summer at her mom's house and it has changed? We have tried talking to her but she wont tell us anything. She also tells her dad when she is mad that she wants to live at her mom's, but like last weekend she wanted her dad to come get her right then and there because she was mad at her mom, and didn't want to be with her either.

So is this a game she is playing, should I be concerned about all the lying, and I want my way now or I don't love you. I mean kids upset and so forth , they lie when in trouble or to prevent being in trouble, but their is a fine line there. She knows it is important to tell the truth and to be honest. She also know that we can't keep secrets because secrets can be hurtful.

So what would you do? Do you think that what happened is being resurfaced? even though there is no other signs but this one? Or is it that she just wants her way?

I am confused and want to make sure that she is okay, but I wont tolerate lying, just because she wants to throw fits. And she is very close to her dad and she is doing the same thing to him, lying, throwing fits.

Like last night, she had to wirte her spelling words, because she was struggling in spelling, so we make her write and practice her spelling words, and it has been working, she is getting a A now, but we keep helping her, she was told to go write the word. She turned the music on full blast, we had already told her she couldn't listen to a mp3 player, as she need to pratice writeing and saying the word, so she turned the radio on, we just told her to turn it off. About 10 minutes later she came out and said she ws taking a shower, we told her she need to finsh writing her words , she went and got in the shower anyways and turned the radio back on for the second time full blast.

When she got out of the shower, we asked her why she did this, instead of doing what we asked, her comment ws I wasn't going to school smelling like a dirty dog, when asked why she turned the radio on when we had already told her to turn it off, because i wanted to listen to it.

When we told her that she could of took the shower after she was finished with the shower, and could have listen to music after she wrote her words, and that she disobeyed our request, she just kept saying, I wasn't going to school and smelling like a dirty dog.

We make her take a shower every night, so why did she say that?