No.
Ad Blocking in iOS 9 is restricted to devices that can handle 64 bit apps. It's probably a matter of performance, since ad blocking on a local device can significantly slow down a browser
There are a couple of older add blockers that use proxy servers. Those should still work with the earlier iPads.
There are a couple of them, but the only one I can remember off the top of my head is Weblock by FutureMind. That's not a recommendation. I don't know enough about any of the blockers to recommend one.