Yes, It works well.
You will install the app on Galaxy S9+ (It is an Android device).
The app you will install on Galaxy S9+, it called as "Target app" or "Client app".
After the installing, you can go to a website of the user control panel to view all tracked data sent from the target.
Also, you can install the app on YOUR iPhone. It named "Monitor app" (or "Server app"). That is not required.
You can see this article about all apps in our system as well as how to install the apps on the devices.