The first question to ask is will it work correctly with the N9?
Nokia Bluetooth Stereo Headset BH-221 is compatible with the following: All phones, music players and other devices that support Bluetooth Specification v 2.1, 2.0, 1.2 or 1.1, Handsfree Profile 1.5 or 1.0
Connectivity NFC (Near Field Communication) for easy pairing and sharing Bluetooth 2.1 +EDR (Enhanced Data Rate) FTP (File Transfer Profile): server (v1.1) OPP (Object Push Profile): client, server (v1.1) HSP (Headset Profile): audio gateway (v1.2) HFP (Hands Free Profile): audio gateway (v1.5) A2DP (Advanced Audio Distribution Profile): audio source (v1.2) AVRCP (Audio/Video Remote Control Profile): v1.0 High-Speed USB 2.0 with micro USB connector for transferring data and charging 3.5 mm AV connector Wi-Fi hotspot Micro SIM card