tvOS Support
The Demo App in ObjectiveC/Ambly Demo has been updated to include a tvOS target. You should be able to use this to establish a REPL into the Apple TV simulator and also into actual Apple TV hardware. This demo app does nothing more than run JavaScriptCore within the app, initialize the ClojureScript runtime, and provide the hooks needed to establish a REPL connection. In particular it doesn't create any UI.
To create your own UI, you could consider using Ejecta, as Ethan Sherbondy has done in this demo:
Presumably JSExport works, allowing approaches akin to the one used in Goby to establish communication between the ClojureScript and native sides of an app. This stuff is so new, it'll take early adopters to venture forth into creating stuff for this platform.