Nine minutes is a fairly normal connection time.... but if you miss it then just get on the next available train and sit in any seat that does not have a reserved sign on it. (I'm assuming this is all on one booking, and that you're looking at an inflexible ticket).

What booking site are you looking at? If it's www.bahn.de you can change your preferences to give you a longer connection time, you can try that if you'd rather get a reservation on a later train and save yourself the "will I make it, won't I make it" worry.

Personally I'd be quite happy with a nine minute connection, unless I absolutely have to be in a specific place at a specific time.

All three countries concerned are in Schengen, so there is no Immigration. In theory there is Customs between Switzerland and her neighbours (as Switzerland is not in the EU), in practice you're unlikely to see a Customs officer unless they are doing spot checks.