Alqamah and al-Aswad bin Yazid report that Sayyiduna Ibn Mas'ud (may Allah be pleased with him) used to say nine takbirs in the two Eids: four takbirs before the recitation, then he would say the takbir and bow; and in the second rak'ah he would recite, and when he finished he would say four takbirs and then bow.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9484