The Samsung galaxy S9 And Galaxy S9 Plus do not come with FM Radio support in the US. This is apparently a mistake and this will be fixed in a future software update.
It has been revealed that support for FM Radio should have been on both handsets at launch, Samsung confirmed to NextRadio the reason for the error.
Samsung mistakenly did not add the NAB FM API to the unlocked devices. Our team confirmed this with them a couple of days after release upon receiving reports the app did not work. Samsung has said it will be in the first update they do, but have not yet settled on a date.
The model numbers are SM-G960UI and SM-G965UI that do not currently work for FM. SM-G960U and SM-G965U are sold through carriers and do work for FM.
Samsung will being support for FM Radio to both devices shortly with a software update, as yet there are no details on when the update will land.