9 weeks! You can do a hell of a lot in that time. And I won't mention what you could do in 9.5 weeks... but seriously, I did 100 hours in one month at ADP, and I did the FAA IR in 15 days, including the groundschool, all from scratch. I did have a few hours of hour building but my total time was still very low when I started. It was a lot of fun! The FAA IR is very pratical based, the UK rating is different in that you are told your entire routing, and it is very structured, whereas in the US I found that it was all as-you-go which was very interesting and fairly demanding too.
Highly recommended. Get out there and get stuck in. Do one IR lesson a day and spend the rest of the time hour building. Get your IR done asap and then go use it by flying across the states and back. I went from LA in a circular route through the mid-west and have also done LA to Key West (and back) and San Diego to Vancouver (and back). Weather interesting at times to say the least, learnt stacks, loved going into the big airports but also the small ones especially mountain airfields, and other weird ones. Great practice and really gets you IR skills in use.