Whether or not something is an essential service is irrelevant under the ADA. The whole point is that you can't get out of discriminating against a group by stating that said group is not your target group. Contrary to your insinuation, the 9th Circuit judges are not stupid - in fact, they have a long history of coming down on the side of businesses.
As for the free services and interpreters, this is a strawman par excellence and not worth replying to. I'll just note two things here:
First, deaf and hard of hearing moviegoers pay for their tickets like everyone else. Second, supporting closed captioning in a movie theater is a ONE TIME cost of $2500 for the equipment. The rest is handled by the fact that digital projection systems already provide all the necessary functionality natively and that most movies are already captioned by the content owners.
And if a theater does not have a digital projection system yet, it is not required to provide closed captions.
So, let's cut the BS already.