I mean yes, if the girl is a social genius and maybe suffers from a rare mental disease that make her think like an adult or something. But what is the odds of that? And even in that nearly impossible scenario you stumble on a new problem. In a normal romantic setting there lies a constant sexual undertone, so if you proclaim that you love a child romantically, then you are somewhat of a pedophile.
Maybe in a situation where you mary a 9 year old. And you restrain your urges, but cultivate a form of social bond until the girl becomes an adult, would make a better argument. But even in that situation many issues arises. Too many problems, so it's best to ban the practice, and we don't want to give pedo's legal pass