An adblocker and f.lux.

Looks like iOS 9 Safari may well be opening the gate to adblocking extensions - there's a pane for "Content Blockers" in the preferences.

Thanks. Do the adblockers work within apps, or only on Safari?

Depends on the adblocker. A simple hosts file is good enough and works everywhere, removing some in-app ads as well but primarily on web pages.