I'm not sure if you already knew this but you don't need a student visa to live in the US for 9-12 weeks. You can apply for a B1 visa (business/visitor category). Technically you are only learning and not working for wages. Once you land a job offer you can get a H1B visa and that's a different story. You'll need an invitation letter for B1 visa and am pretty sure the guys at appacademy will furnish you one if you are selected. Hope this helps.