I had a very similar issue to this after installing a9lh on my n3dsxl, it just would not connect to the internet to update and it was on the same firmware as you even though the blue bars on the main menu said it was connected. My work around eventually after a lot of hair loss and worrying was to patch in all your router settings manually from your wifi, don't connect auto method, just type in all your wifi settings in manually, IP Address, Gateway Address's etc.. and double check they are correct for your 3ds else it wont connect. That was the only way I could update in the end, give this ago see how you get on it worked for me.