Yeap, I had this issue with my iPad Pro 9.7 too. It seems defect, since you can turn wifi off and on, then it works for few minutes and gets stucked again. There was a post on a official apple forum saying that you should check the band of your router: for instance is your iPad running on 5ghZ? IF yes, change it to 2,4. I don't know if it's a software or a hardware issue, but in fact it is an issue since it only appears with the 9.7 iPad Pro and no other device.