Can I list tentative invited talks on my CV? I am a graduate student in mathematics currently applying for jobs in the US, mostly at small liberal arts institutions.

I have accepted an invite to give a talk at a school in mid-November.  May I list this talk on my current CV and expect people to realize that as it's dated "November 2016," it is scheduled but has yet to happen?  Do I need to mark it as tentative?  Or should I simply leave it off?
In terms of status-enhancement or proof of merit, the actual giving of the talk is of almost no consequence. The invitation is the thing that "proves" status and merit (such as they may be). So, yes, list it, all the more considering that you probably don't have many such episodes to put on your CV. 

For that matter, if you yourself had some (unfortunate, presumably) reason to cancel from your end, still, you did get the invitation.

From their end, to cancel your talk after issuing the invitation would be a fairly severe gaucherie... so I'd bet it won't happen. Even if it did, almost-surely the official reason would be some funding problems, not that they've discovered that you're a poseur and a bad person, etc. So the status and virtue leading to the original invitation are not diminished.

Being invited to give presentations is a kind of proof of one's relevance to the research community. 

There are rumors of "an internet", supposedly allowing easy, massive, long-distance asynchronous communication without the expenses and perils of long-distance personal travel, but until that possibility is assimilated into the academic community... much like the notion that "publication" could mean literal publication, rather than running a status-and-merit gauntlet... :)

Joking (???) aside, it's not the literal giving of the talk, and is not the literal publication in refereed journal, that confer status or prove merit, but the invitation (resp. acceptance).