Hi is there a way that I can play the same shelter on both of my iphone and my ipad. As I don't always have my ipad with me and I would like to continue playing on my iphone.

If you mean syncing two devices with the same game, I would say "no". Since there is no server side to the game, the game data is not saved anywhere but on the specific device, so there is no data to sync to another device.