The 9-Euro-Ticket is coming! From June, you can use it for the whole month on local and regional transport throughout Germany. The ticket is already available - for example, in the VVS-app, from Deutsche Bahn or other transport associations.
Edit (09.06.): You have already bought a VVS-StudiTicket for the summer semester? This is valid as a 9-Euro-Ticket in the months of June, July and August - if these months fall within the validity period of your ticket. The money you paid too much will be refunded to you, and the solidarity contribution will also be taken into account (pro rata). You can apply for a refund of your VVS-StudiTicket from mid-June, for example, using an online form. You can find details on the website of the VVS.