Google is enhancing the Pixel 9 series with an "Audio Search" feature for Circle to Search, allowing the app to listen to music and accept humming or singing for queries. An icon will enable users to initiate music searches by tapping it, which will display search results after listening to music from services like Spotify. Users will also be able to sing or hum songs to perform searches, similar to existing features in the Google app and YouTube Music. Additionally, there may be a quick informational bubble when opening Circle to Search, and Google is planning to introduce split-screen support for this function on Pixel devices.