From Sonic & Knuckles Collection for the PC:
http://info.sonicretro.org/Sonic_%26...onsole_version
Sound Coordinator: Masaru Setsumaru
Sound Arrangers: Shigeaki Irie (USP), Masaaki Nishizawa (USP), Goro Takahashi (USP)
So I guess Setsumaru was the one who created those nine replacement compositons.