Some of iOS 9 users report that they find problem on their iOS 9 when they want to use their text box in their Messages app. They find that there is a gray bar with “0.00” showing at the end appears on top of their text box and disturb the texting message process.
It covers the space to type messages instead of it supposedly just appear when you are recording audio with your device. This problem surely irritating and it disturbs the main function of your device because you cannot send messages with your device.
If this happen to your device, you can try to fix it by do the double tap at the Home button and swipe the Message app up to close this app. This step is quite successful but it could be a contemporary solution before the problem return again any time.
You can try other option by turning your iPhone off and on again to solve your problem. However, this option is also could be a contemporary solution before the problem back to your device.
To fix your problem completely, you can try these following steps: please tap the Settings, then tap the Messages, and please turning on the Show Subject Field and Character Count. You can go back and turn them off again if these steps could overcome your problem.
You can try other steps by going into the Settings, then tap Messages, then please turn iMessage off to get rid the grey box, then you can turn iMessage on again.
For your information, this problem is also listed as the bug fixes in iOS 9.1. It is worthy effort to updates your iOS device to fix your problem easily if you haven’t update your device and you find this problem occur in your device.