dmVI

I did the same in New Zealand and it was a massive hit with the kids! Great site with a series of tutorials, in browser barebones Minecraft game to see the results of your code and a great full version Minecraft setup with dedicated worlds where the code is loaded as book objects inside the game. HIGHLY recommend checking them out: https://www.learntomod.com/

They also offer free teacher and student accounts with the ability to limit time. Can't say enough positive things about the service.

Quick check on my iPhone shows that it allows for (and is set to) "While Using the App" for location access settings. Running latest iOS release.

Minecraft mods are a GREAT way to introduce kids to programming. Take a look at the awesome work learntomod.com have done. We recently held a Junior Hackathon, http://jhack.co.nz, based on Minecraft this weekend (in Auckland New Zealand). It was a MASSIVE success and the kids had an absolute blast!