I dont think you receive a top player in return in this scenario. Carolina would look to have a top young QB with their alleged #1 WR and an elite pass rusher on the other side that can make splash plays on any down and distance. They are more likely in a position to send off extra picks (which, hey, take every one they got from SF).
JSN is a great option at 9 and the only reason to be skeptical on that end is any lingering thought on his past injury. A dedicated slot receiver that is worth targeting 8 times a game is a fine use of a top 10 pick. His agility will open up those short passes that Fields announced that he will work on in the offseason, which will then pull safeties down so Claypool and Mooney have chances downfield.