Welcome to the forums!
Nine pounds is not a backpacking tent, that's for sure, but you wouldn't be the first to carry one, that's for sure too.
Your milage doesn't sound like too much, but that really depends on your total pack weight and how well you handle it. If you're lugging 45 lbs or more, 10 miles might be more than enough to wear you out.
I'd load the rental pack with all the gear I'd be bringing and do a couple miles to see how it feels.
As far as food goes, you can get freeze dried meals, like "Mountain House" from Wal-Mart for around $6 each. They say on the package that they serve two, but after a long day hiking you'll be eating one all yourself with no problem. I think they're pretty tasty considering the weight. There are other brands that may be better rated by members here that you might want to look into as well. Check out the links on the sidebar of the pages here for more on that.
The main thing you need to remember is to take a break every now and then. If you haven't already, check out the recent thread "Your Most Profound Advice
". Although not fully elaborated, most of what's in that thread is really pretty good advice and shouldn't be dismissed or ignored.
Have fun, and post a trip report with pics if you can, we'd all love to see where you went and hear about how your trip went!