If the last EN knew from Villa Monterey was that the Buick was going westbound from there on Cherry River, the Buick would be going towards his home. It's Mogg's supposition that EN saw them on Carmel Peak, but if Mogg is wrong and the last place EN saw them before the U-turn was at the time of the shootout, then it would be logical for EN to assume the Buick might be going to his home.
Yes. I think what EN meant is that he thought his home was the intended destination of the Buick. I don't think he literally saw the Buick pass his house.