We know that Han Solo had been to Tatooine before, as he had run-ins with Jabba the Hutt, but there’s every reason to assume he went there a lot, perhaps because his mentor taught him there was always work to find there.
Of course, there’s also every reason to believe that this could be Mos Eisley and that the Han Solo movie will have scenes that take place on Tatooine.
We know that Han Solo’s mentor Beckett, played by Woody Harrelson, is a criminal, so it’s just the sort of place he might hang out.