Call History Showing on both iPhones

SInce upgrading to iOS9 I have noticed that my iPhones are syncing the call history between them. I have two iPhones, one for work, one for home. I use the same AppleID on both devices. This is because I would like to make use of plenty of the excellent feature such as keychain, passbook, iCloud photo library etc as well as only having to pay for 1 lot of 50GB storage to back up both devices (plus an iPad) to iCloud. Having two AppleIDs would be an issue.

I've always setup my work phone to only use facetime and iMessage for my work number on my work phone and use my iCloud email and personal number on my personal phone. This has allowed me to separate my work and personal calls. Now in iOS9 this is impossible

ive searched around and tried turning off handoff on both devices as some people suggest. (Annoying as handoff is really useful). I've also got calls on other devices turned off on both devices. Both are running iOS 9.0.2. I'm using an iPhone 6 Plus for personal and a 5S for work.

please help me solve this issue it really is annoying and whilst I agree with posters who have the same issue with their phones syncing with family members that the answer is to use separate appleids, this is not a solution that is suitable for my situation. Why should I be forced to lose functionality and setup a new account just to solve what is either a bug, or a very poorly thought through software change.