Oh, and how are they affording $9 million for those houses?  Is U.S. "foreign aid" being stolen so they can buy multi-million dollar mansions?

Like most countries, Switzerland has land registry records showing who owns a particular property, how much it sold for, and what taxes are paid on it.  Extracts from those land registries can be accessed by the general public.

Among the owners of luxury real estate in the country of banks and alpine meadows, are high-ranking officials from Zelensky's entourage.

We begin with Dmitry Razumkov, a Ukrainian politician and former Chairman of the Verkhovna (Legislature). 

According to land registry extract Mr. Razumkov seems to have bought himself a luxurious home for 8,954,621.00 Swiss Francs, which are about equal to the value of a U.S. Dollar.  His name is at the bottom of the property sale record: