If you don't have USB etc in the arm rest then it sounds likely yes you do have an MY08 car on an 09 plate. Also check to see if it has HIDs - another difference between the two.
To be sure, you will need to check then VIN number when you get the car. If it is the older model, well... could be worse - I have a 59 plate which is MY08
Ha, but seriously the biggest gripe for me was lack of iPod connectivity like yourself and as part of my deal on the car I got the Honda kit fitted FOC. It's fine for my purposes but not the most user friendly system out there, others recommend Dension as you say and Dice and XCarlink. You will find loads of comments and opinions if you search the forum as to which is best for your needs.
They should all charge your iPhone, the non-honda units also don't freeze the controls when connected unlike the Honda OEM one and yes control through the steering wheel for playing music applies with all of them.
As for Halfords, I remember someone posting about this service a while ago but have no idea if they took it up - personally I've never seen it advertised or made clear in a branch. It's your call as to whether or not you'd be happy letting them loose on your new car???
Mine was done by my Honda dealer (again, part of the deal) and to be fair they did a very neat and tidy job. Plenty of members have tackled the install themselves following the How To guide on here and got on just fine.
Good luck with the new ride and let us know how you get on