Well there are couple of things you need to take care of for Google play to not to filter your app for Tablet Devices. But if you are seeing the app on some tablets and not the others, then please make sure that those devices are in the google play supported from the link below
Here are some tips
1. Make sure that in your AndroidManifest.xml file you have the following set
<supports-screens android:largeScreens="true" android:normalScreens="true" android:smallScreens="true" android:xlargeScreens="true" android:resizeable="true" android:anyDensity="true" />
You see those largeScreens and xlargeScreens up there set to true. That will tell the google play store that your app support those screen sizes.
2. The second one is logical too. Be aware of the permissions your app need and your app requires. Because most tablets may not have features like for example: Telephony, SMS, Flash Light, Camera, GPS. So for those of those permissions that are not a must, make sure to flag them as not required like below
<uses-permission android:name="android.permission.FLASHLIGHT" android:required="false"/>
Pay special attention to these permission especially when you are using Phonegap/Cordova to generate the project using their command line utilities as they tend to add permissions that are not needed for your app and most likely might be the reason for Google play to filter your app for tablet devices as they might not have all these features.
3. Make sure that you have you screenshots for both 7″ and 10″ devices on your google play publishing page.
Publish your APK again with the above changes ( don’t forget to change your VersionCode in your manifest file) and after couple of hours you should see your app appear for tablet devices too.
You can also make sure that your app will appear on the tablets by looking at the supported devices list in the APK tab section of the developer console and searching for couple of tablets or simply search for “tab” and you should see tablet devices from manufacturers with a green check marks like below