Following yesterday’s release of tvOS 9.0.1, Apple has today seeded to developers the second beta of 9.1. This update comes one week after the initial release of tvOS 9.1 beta. This version of tvOS brings limited Siri support for controlling music and mostly other bug fixes.
Developers can install the latest beta of tvOS from the Settings app or if you’ve downloaded it for the first time, install it by using a USB-C cable and connecting it to your computer. Then install the IPSW via iTunes.