Dynamics 365 upgrade to ver 9. Plugin Solution Connector issues

Greetings.

We’re preparing our online Dynamics 365 (ver 8) to upgrade to ver 9.
There is a question regarding Marketo integration:

Is someone tested Plugin Solution with CRM version 9? Is everything operational?
I am little bit concerned because latest version is for Dynamics 2016 and in latest CRM update there was major security protocols updates it can affect connector.

P.S. Does regular users like us (not partners) has ability to set up sandbox?