I think normally the runner has to be the one to post the record. Is there any way to contact them? I think it'd be really cool to see their record on here

Under the filter option emulator runs are not hidden by default like a lot of games and you are able to submit runs using an emulator, but so far none have been submitted, so the rules could change when that happens. In terms of what emulator to use, Citra would be your best bet, but 3D Land runs poorly along with a lot of other games so it's far from ideal.