All this dodgy pirate shit is exactly what is causing you problems:

"megabox hd, movie hd, and mobdro"

Go into Android Settings > Apps > Downloaded Apps > select App > Uninstall

There is a whole MINIX support forum for your device: http://www.minixforum.com/forums/neo-u9-h.158/

I suggest you use it. You may even find an unofficial Android TV ROM in there as well ;-)

This sub is for devices running the official TV focused fork of Android by Google, not devices running touchscreen Android with few TV focused changes except a decent big picture launcher usually. Sites like FreakTab have sections for those devices you could check out. If you don't want to or can't root your device (a lot of them come prerooted) you could look into a DNS based adblock such as PiHole

Get a refund on that junk box. Your pops got swindled.

You shouldn't be asking "all these ads popping up are completely normal so how do I hide them?"

You should be asking why there's ads popping up in the first place. Imagine if you bought an Android tablet and it was doing that. How fucking jank would that be?