Yes, the Apple Camera Connection Kit is what I use to connect my Yamaha keyboards to my iPad via USB-MIDI. But be sure you get the correct one. Older iPad models had a 30-pin connector and used the older "Camera Connection Kit"-- which can be hard to find, since it was discontinued a few years ago. But newer iPad models have a Lightning connector and use the newer "Lightning to USB Camera Adapter," which is readily available in most Apple stores.
Beware that some Apple Store salespeople might not be familiar with connecting USB-MIDI keyboards to an iPad, and might suggest that you could possibly just plug the USB connector on your iPad's charger cable into the keyboard. But you absolutely need either the "Camera Connection Kit" (for an older iPad) or the "Lightning to USB Camera Adapter" (for a newer iPad). You need to plug the squarish-shaped end of a USB cable into the back of the keyboard, and plug the flattened-rectangular end into the iPad's adapter.
I haven't tried using a Bluetooth connection yet, so I can't answer that. However, I've heard that Bluetooth can be unreliable as far as the quality and stability of the connection, although that might not be a concern as long as your iPad, iPhone, or iPod touch isn't too far away from the keyboard and its adapter. If your iOS device is propped up on your keyboard's music rest or whatever, then the signal should be fine.
In that case, make sure you get the "Lightning to USB Camera Adapter," not the old "Camera Connection Kit."