My visa exempt stamp says I'm admitted until 09 Feb. Does that mean I can leave on the 10th or do I have to leave on the 9th? My flight out of the country is 08:00 AM on the 10th and I don't really want to go through all the hassle of a 1 week extension just for staying 8 hours past the stamp date.

Also, I have a new passport since I entered the country. Do I need to go to immigration and transfer the visa exempt stamp to my new passport before I go to the airport or can I just show both passports at airport Immigration as I leave the country?

I tend to worry too much but I thought I'd ask as I've heard they are cracking down on overstays. I've been coming and going for 7 years here and have never overstayed or done anything out of line and I don't want to do anything to upset anyone at Immigration as it is essential that I be allowed to return and see my Thai wife and child.

Thanks in advance for your advice.

You are unlikely to be fined for an 8 hour overstay if leaving via one of the Bangkok airports but you may get an overstay stamp.

Just show both passports when leaving.