Whilst there are some things you can do to restrict what your kids can do on an iPhone/iPad (see previous post here), the level of control available to you is nowhere near as granular as most parents would like. In Android, however you have much more control through 3rd party solutions such as Net Nanny. To see how to restrict particular apps, the Google Play Store etc I recommend you go tak e a look at a good video walk-through of what you can do, so go take a look – here. Product info can be found here.
Disclaimer – I do not benefit from mentioning this product except from the warm & fuzzy feeling I get by perhaps helping like-minded parents protect their children against some of the nasties out there on the net.