After 5 days invested in learning Ember, I am having trouble with Ember CLI

People are apparently having success with this solution, maybe that’d help you. But you could just wait for 1.10 to be out of beta. Whether HTMLBars is enabled shouldn’t affect the code you write, just performance. Get started, and once 1.10 is released, things should be ironed out.

As for ember-cli, it does say

Although potentially exciting, this is still really a WIP, use at your own risk.