When using a hardware keyboard with the iOS 9 device, you need to go into Settings > General > Keyboard > Hardware Keyboards and match the layout with whatever your keyboard's key printing is. Unfortunately Apple supplies only a limited selection of such layouts, so it's possible an exact match may not be possible. For example, if your keyboard requires the British PC layout, you are out of luck. I think only one normal iOS keyboard has no hardware layout at all: Tamil.
Here is a list of the layouts available.
As far as I know, 3rd party keyboards do not include hardware layouts.