I think there is something I don’t see.
Support for a specific eBook format is not a property of Android itself, but depends on which particular reader applications one uses. In Android, there are some, with more or less similar and large set of supported formats. There are, however, several proprietary (so called walled garden) formats with very little support outside the allowed platforms. Amazon eBook formats are on this category, so do not expect to easily read them outside the Kindle Reader app.
But what exactly are you trying to achieve? And how calibre enters into your situation?
If your books are in the Amazon “cloud”, then you have no problem. You can read them on any device with the Kindle Reader app installed, PC, Tablet, etc. You only need to add them to your device list on your Amazon accout settings. You do not need calibre in this scenario and besides, you can configure your tablet to use only the WiFi.
If your books are in the calibre library (and DRM free), you should be able to send then to your device (USB, email) or to the SD card of your device plugged on the PC or download to your device from the calibbre http or OPDS interfaces. This process may or may not need file conversion, depending on the original file format and its support by the reader application you are using.
But, if I understand it correctly, you want to use the Kindle Reader app in your Android tablet. In that case, you would have to convert the eBooks to either .mobi or some of the native/proprietary Amazon formats and send them to your device using the Amazon service. I am not aware of a simple method of directly importing your locally stored books into the Kindle Reader app. On my opinion, the easiest in this case would be to use some other Reader app.