I've already installed a content blocker on iOS 9 and the difference is night and day. Everything loads damn near instantly, even on my awful Sprint service. There's going to be some sort of major shift once the general population are all using adblocks.
You can roll your own content blocker (it's just JSON after all) and install with Xcode. Xcode will allow you to install content blockers on 32-bit devices that way.
If you don't want to roll your own, you can use this: https://github.com/krishkumar/BlockParty
There is already open source stuff like BlockParty, and a few others popping up on GitHub. Then again, the average person isn't going to be hipster enough to compile their own blocker.
BlockParty (the same as the iOS one) has a Safari Extension for Safari 9 on El Capitan that installs their blacklist.
https://github.com/krishkumar/BlockParty/tree/master/BlockParty%20-%20Desktop%20Safari
I also only have 32-bit devices.
I installed BlockParty from GitHub to block ads. It's an iOS 9 content blocker, and works decently well.
I also use Gammathingy for the F.lux/Night Shift effect.
I'm going to have a go at making one now you don't have to be a dev to install apps with iOS 9. I think some of the apps available are a bit overpriced considering the result of their existence is removing income from others. I know adblock exists because the ad industry is out of control, but the people losing money are the websites, not the ad companies. While websites cry about Adblock, Google posts records.... bit suss
There's a few places to help get started blockParty ab2cb content_blocker_tips