I never thought I the day would come where I would be able to see this movie in a theatre.
I never thought I would see the day where I can see this movie in a theatre.
I never thought I would be able to see this movie in a theatre.
「この映画を映画館で観られる日が来るなんて思わなかった」は英語で I never thought I the day would come where I would be able to see this movie in a theatre. といえます。
I never thought I would see the day where I can see this movie in a theatre.
I never thought I would be able to see this movie in a theatre. (この映画を映画館で観れるなんて思わなかった)
ともいえます。
I never thought I would see the day =「この日が来るなんて思わなかった」
映画館 = theatre or theater
theater はアメリカで使われてます。theatre はアメリカ以外の国でほとんど使われています。