I have an iPhone 7 Plus and I want to get an Samsung Galaxy S9 I live in Canada so I can only get the snapdragon 845 chip I want a phone that will run a game called PvZ Heroes (A card game) at 60fps or at least 49 I know that the single core Geekbench is lower but the antutu benchmark is higher so will be faster or wait for the next Samsung phone?
The SD845 in the S9 is the fastest chip available for Androids this year, excluding the Exynos. The next one to be faster will be next years Galaxy S10, because part of the deal with Qualcomm and Samsung is that they get to use the chips first before anyone else.
As for performance, Samsung phones are typically set to optimized/balanced performance to avoid overheating and overtaxing the battery. So even if the phone can normally run the game at 60fps, it would depend on how big a load it is on the device.
To get around this, you have to go into settings then set it to Game Mode/Performance Mode. Then go to the Game Tuner app and set the game to use max performance. That app also lets you put an FPS cap on the game.
You could also look into the OnePlus 6. Samsung designs its devices as an all arounder. It may not be the best at everything, but it does everything so well that there really isn't any compromise with a list of features that is only missing the kitchen sink. OnePlus on the other hand focuses more on performance, so while it does not have Samsung goodies, it's going to give you what is possibly the best performance you can squeeze out of the SD845.