For scenarios such as these where you require fine control over the application rooms lifetime, using the cloud poses some problems. This is because updates to a room's properties (start time, end time etc.) have to be done from the client side. This means that you will require something like an admin app (which will also use the client SDK) but will always be present and will manage how the rooms lifecycle and properties are updated.
it is recommended that you use AppWarp S2 which is the on-premise game server solution. Its similar to AppWarp cloud but also allows you to extend the server side. So you can build your own server side controls which will manage the lifetime of the tournaments and do the realtime judging of winners and rewarding coins etc.
AppWarp S2 though is not a cloud solution and developers have to host the game server themselves (you can use Shephertz GPaaS also for that).