These comments are from Nik:

iOS 9 is out and has brought a number of changes. Some major and some not so drastic, but mostly improvements and a clean up of iOS 8.

In short iOS 9 has brought the following:

Greatly improved text selection abilities both using touch, braille and keyboard commands
Introduction of keyboard commands such as command+r to reply or command+shift+d to send a message. All of these commands are available to the Voice Over user, but are undocumented except for if you press and hold the command key with a blue tooth keyboard with and iPad. The different keyboard commands will then be displayed on the screen. This window does not read with Voice Over.

Better and more stable BSI (braille screen input).
The ability to set tap speed or issues with multiple touches. I especially find this one interesting.
Increased speed and more features implemented with braille displays. This is great, but your braille display can too easily get unpaired from your device, I.E if you turn on airplane mode and turn it off again you need to unpin it again. This is a major issue if this is your only way to control the device. Apple is aware of the issue and I am hoping that it is resolved in iOS 9.1 which is supposed to be in the works already.
Hearing aid profiles, for hearing aids that are “Apple enabled” you now have the ability to set individual profiles for each hearing aid or for what activity you are doing, I.E listening to music or making a phone call.

Hey Siri, do you understand me? This is new in that it gives you the ability to train Siri to understand you if you have a speech impediment or like me and you have an accent.
As far as main stream features,
there is a news app that looks rather good and is fully accessible..

The notes app has gotten a great deal of work done to it. It now supports images, links and greater formatting capabilities. Still not a fully equipped word processing tool, but it is easy to use and offer many of the basic features you would look for in a writing tool.
Maps now has public transit info. Yes, this is nice, but Google maps has had that for a long time. It does however have a nice category search available now.
Mail, you can now add attachments to an email from within the message it self rather then using the “share” option within Dropbox or other Cloud storage you may be using.

Cloud storage, Apple has now added an app called iCloud drive that lets you interact directly with your files and folders just in the same way as you can with Dropbox.

Apple pay is now called wallet instead, but functions exactly the same.

Split screen on iPads. This is only available on the iPad Air 2 or later. I can see this really coming to its full advantage with the new iPad soon to be coming out.

Siri and proactive search, As a Voice Over user you now have greater choice with what voices are used for Siri. That can be set under the Voice Over Speech settings. As for proactive search, it is supposed to be a more intelligent and context sensitive Siri, but I don’t have much first hand experience with this as of yet. I suspect we will learn a lot more about the new Siri over the next couple of months.

Head phone activated apps, when you plug in headphones to the device the lock screen comes up and shows you the icon for an app iOS thinks you want to use. I have not seen this be consistent at all.

Contacts and calendar, there is improved integration of these apps within each other and Mail and it looks like it is going to make it very easy to manage who you see and when you see them. Even less of an excuse not to keep everything in my head.

Keep in mind that the above is a summery and I am sure that we will find out about and learn other things about what iOS 9 does or does not do. However, the one question I get often is “Should I upgrade my device or should I wait?”. I definitely think you should upgrade unless you are dependent for your device and braille display as your main communication tool. If you are, eat for the 9.1 release and lets hope that Apple has fixed the braille connectivity issue.