Musannaf Ibn Abi Shayba 3:3332

Hushaym narrated to us, he said: Dawud informed us, from al-Sha'bi, who said: Ziyad sent to Masruq, "Occupations occupy us, so how is the Takbir in the two Eids?" He said: "Nine Takbirs." He said: "Five in the first [Rak'ah] and four in the last, and he should join the two recitations together."