Yeah, if memory serves, it requires the temple, but only says "Sacred Band" not whether it is infantry or cav or both...

I didn't have much luck with the "Scared Band Infantry" on VH/VH. I would save the money and time to build long shield cav...or build the Sacred Band Cav instead. You can drag along a few infantry for sieging and holding a bit of line for any ranged units you might get, but with Carthage, cavalry is the answer.