iOS 9 Jailbreak
Developers have failed to release an iOS 8.3 jailbreak and it's not clear if they will get one out for Apple's iOS 8.4 update. You can, however, count on some kind of iOS 9 jailbreak release in the future.
Given the work that developers have put into the iOS 8 jailbreak, it's clear that there is still a market for iOS jailbreaks. And while we may not see jailbreak developers release an iOS 9 jailbreak right when the iOS 9 update is released, we would be shocked, shocked, if they failed to release one at all.
It might not come until Apple releases iOS 9.1 but we'd expect there to be an iOS 9 jailbreak down the road. The community is still thriving.