No president has tried it before. Whether he can get away with pardoning himself has yet to be seen. For him not to get away with it would require someone to bring some sort of court case challenging it. And to bring a case, they have to have “standing.” (That is to say, they have to have some credible justification why the self-pardoning action the president took wronged the petitioner in some way.) Which would probably require some legal argument that has never been made before.

I’m guessing Trump probably could get away with it, but given that no president has tried this, we’ll just have to see for sure.