A good way to grip something round like the pin in the crank is with a drill chuck. There may not be enough protruding, and smaller chucks with small jaws with a pronounced taper will give better access. I have an old chuck saved from a scrap drill that I use. I have removed more than one of these pins in the past and have not found them to be very tight. A little gentle wiggling and twisting while looking closely at the pin with a magnifier to see if it is moving should also help.