Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated: I spent the night at the house of the Messenger of Allah (peace and blessings be upon him). When the first dawn (the false dawn) appeared, he (peace and blessings be upon him) got up and prayed nine rak'ahs of witr, saying the salam after every two rak'ahs.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11840