9 Shvat is the yahrzeit of Reb Chananya Yom Tov ben Reb Yekusiel Yehuda (Yetev Lev)Teitelbaum ZY"A. He wrote the sefer Kedushas Yom Tov. His sons were the Satmar Rebbe, Reb Yoel ZY"A, and the Atzei Chaim, Reb Chaim Tzvi ZY"A. (Note: many places list his name as Chananya Yom Tov Lipa, but this seems to be an error because on the Satmar Rebbe's matzeiva and in his sforim it doesn't say Lipa.)
Also, yahrzeit of the Alter of Slabodka, Reb Noson Tzvi Finkel ZY"A. See here for more info and a beautiful picture of his hadras ponim.