Your way of adding interactions in RP8 is no longer the most efficient in RP9 – opening the same file using different Axure versions is pointless.
Actually, the screenshots that you’ve shown prove the point opposite to the one you made.
In Axure RP8, each time when you should add a new element to the interaction, you created a new interaction instead. For example: You created 8 different “Hide” interactions (to make RP8’s interface more legible) which could be done with one interaction instead (this way it’s still legible in RP9 and also it’d take less precious space that you ranted about)