I heard about 9apps from my friends so one day I downloaded it from Internet. It contains thousands number of Android application so I downloaded some applications from it but I found some errors on some app. After downloaded the app when tried to open it, it didn't open and showed me a message that it is unfortunately stopped. It is not like Google play store. It also contains some fake apps. So after download some apps from it I stopped download from it. I think it is not as good as Google play store.
I don't recommend you to download this app.