I was just wondering if someone with a criminal record that has theft under 5000 on it can leave the country and travel to the US?

If you have a theft under offence you can be denied entry to the US.  Once your pardon is granted you should be safe for travel to the US, however if you get denied then you will need a US Waiver.  Most other countries you will be safe for travel even with the theft under $5000 offence, however it is better to remove the criminal record and then you will be completely safe for travel.