A:AnswerIt will work for the S9+. I have one but it charges relatively slowly even when it says fast charging. It's not overly slow just not as fast as plugging it in directly.
A:AnswerThis charger is capable of charging the S9, however thicker cases may prevent the phone from charging. Try centering the phone on the charger without a case to verify this.
A:AnswerIt depends on the field strength of the charger and the proximity of the charging coils (between charger and device). More than likely, it won't charge two phones simultaneously as the coils need to be within a few centimeters to charge properly.
