that depends on the country. In germany it is called and issued in german as internationaler Führerschein which is translated then as permit but actually in original the meaning is license/paper. Just to say 😅
Francesco Marescotti In practice, you won't be able to stay for nine months because you apply for the visa a while in advance to be on the safe side and that shortens your usability.
if you have rest days when you exit Thailand you can buy a re-entry to keep them for your next entry.
you maybe are not able to get a visa on arrival - only certain countries get that.
you can't get a Tourist Visa during you are in Thailand if you will not come back from your home country.
every time you are arriving at Thailand without an active visa you can enter visa exempted for 30 days and do an extension inside Thailand for another 30 days.
you can enter Thai land borders visa exempted 2 times a year.
you can apply at your trips to neighbouring countries for a single tourist visa at the thai embassy/ consulate there.
this will give you 60 days at Thailand possible to extend for another 30 days at immigration offices in Thailand. So 90 days.