prevent google play from showing books only I want to prevent google play from showing any books because there are some inappropriate books and google play's parental control didn't work perfectly(as they said not 100%).  

I don't want to disable all google play, I still need to install apps .  

I've seen this question and looked under Settings -> Apps -> All, I see google play store and google play services but I don't see "google play books" or anything like that(I see "content share" but I don't know if this is what I want).   

I have device sony xperia P android 4.0.4 but I need instructions for a Samsung device as well(my aunt's one, don't recall device version).

I prefer not to "root" the devices(but I'm ready to do this if it's the only option).
If the Google Play Books app is installed then you can disable that using the method you linked to in your question. However, the store-front of Google Play Books is part of the Google Play Store and cannot be disabled. Maybe it could be hidden with some root modification but I doubt whether such a modification to do this exists. I suspect much of this is managed on the server-side (as Andrew T.) mentioned and so hiding it would be the only possibility.

You can make sure that no books can be downloaded without the password for the Google account by opening up the Google Play Settings and setting Require password for purchases to For all purchases through Google Play on this device. Note that this also affects apps, music, etc.

Sorry this isn't possible! I suppose you could always send a feedback request to Google...