You can now downgrade iOS 9.0-9.3.4 to iOS 8.4.1 firmware without SHSH Blobs. The downgrade is carried out by a method called 'iOS Spoofing'.

When a new method comes out, Apple is quick to patch the vulnerability it exploits by issuing a new iOS update. If you were to accept such an update, you'd no longer be able to jailbreak your iPad, iPhone, or iPod touch unless you could roll back your firmware to a version that could be jailbroken. But Apple even takes things a step further and stops signing older iOS firmware versions, which makes downgrading next to impossible. Microchip Pickit 3 Software. This is where your SHSH2 blobs come into play. If you save your current SHSH2 blobs, you'll always be able to roll back your firmware to the iOS version your phone is currently running — even if Apple stops signing it. This means that if a jailbreak method for your current iOS version is made available after you've updated to a future iOS version, you'll be able to do a custom restore with iTunes to downgrade your firmware to the version that works with the jailbreak method. In short, it's sort of like future-proofing jailbreak.