Here is my setup that I have installed in my truck and works great. It is a Raspberry pi 3B with a 5in touchscreen mounted in the dash. I have a relay that turns on a 12v to 5v 3a convertor to power it. then have the obd1 connector to usb. I have a second usb out to a connector in the lower dash for the usb stick to copy the datalogs. It boots in about 45 sec and is running android os so I have the android tuner pro app. I don't have to worry about taking the laptop or it not being charged just power on and datalog, also it can be used as a digital dash display. 20180212_220317041_iOS.jpg

not sure about android but for the iphone/pad they make a thunderbolt out to 2 connectors so you can charge and connect to a device, maybe they have something like that for your tablet. The other possibility is to get a bluetooth obd1. I had one a few years abo when I used the tablet to datalog but when I went to the raspberry pi I sold it and just used the usb to obd1