Holden Barina 2007: Good first car for p-plater?

You're right to be concerned about the safety of the 2007 Barina, it only had front airbags and ANCAP rated it only two stars. Side front airbags weren't made standard until November 2008, after which it was given a four-star rating. You would be much better off going for the later, safer, model. I also agree with your thinking about having him drive a manual, that way he'll be a more capable driver. Based on your assessment of the condition of the car you're considering it would be worth around $4500.