You are allowed to travel in your country of residence on a maximum of two travel day  (00.00-23.59 CE(S)T) so if you travel to and from München on 2 different days you will will have no home country travel day left for your return to Germany. 

Maybe you can use the 9 EUR ticket for one of your travels in Germany?

You can use only 2 days of the 5 days in your home country (it also applies to transit through your home country). 

After using 2 days in your home country you have to pay from the last station before your home country or the border fare point. 

I assume your home country is Germany.

Interrail allow you to use your pass in your home country on any 2 days of your journeys. It does not automatically check if your journey crosses in or out or even if you leave the country on either of those days, simply that you have used your pass in your home country. On those days, just as all other pass days, you can use your pass for as many trains as you want both in and out of your home country.

I believe it does though also register any journey which passes through your home country, even if you don’t get off and would take one of those days, possibly stopping your return at the station before the border.

So, although these are called inbound and outbound days, you can use one of these days to both enter and leave (i.e. cross) your home country and then the second for your return to your home country.