Carthage and Canaan did share many cultural traits, and the Carthaginians also called themselves Canaanites. It's quite plausible that the Carthaginians would indeed worship Moloch and make sacrifices to that god, and that the mentions of child sacrifice in classical sources about Carthage are based on such.
I think it's still inaccurate to refer to Moloch as Carthaginian rather than Canaanite. The latter is obviously correct, though a bit vague. The former is contested and not as clear.
