We are visiting the Grand Canyon in early March and were wondering if anyone had any suggestions on a good tour we could do with a nine month old. We are a bit limited, but she travels well.

Assuming you have a car, there's absolutely no reason whatsoever to pay for a tour to see this place. Just drive around the Rim (South, I'll presume), stopping at as many overlooks, and at as many times of the day, as you can. Also, get photos of your infant with The Canyon in the background, so she will be envious that she doesn't remember being there.

If you do NOT have a car and plan to pay someone to take you to The Canyon, be 100% certain that you are NOT going to the West Rim. It's not a bad place to go, just not worth the money you'll spend.

Depending on the time of year, make certain that you shield the child from the Sun. The air is thin at 2100 meters, so UV exposure can be quite strong even if the temperature is mild. An infant can get badly sunburned before you realize what's happened.

Although I can't recommend a hike INTO The Canyon with an infant, I do recommend you walk along the Rim Trail. You'll probably get photos like this:
http://www.ianandwendy.com/travel/wp...ll-250x187.jpg

Just look at the various View Points. Visit a Visitor Center. Maybe a helicopter ride. I don't think I would hike down with an infant unless you have one of those carrier backpack things. And then I wouldn't go very far at all. And if there is snow I wouldn't go down at all.

I don't know which direction you are coming from. But you could drive thru Petrified Forest if coming from the east or Hoover Dam if coming from Vegas.

Have a meal at El Tovar. Maybe lunch or breakfast since you are with an infant, but I would imagine dinner would be fine also. Our daughter would be asleep or wide awake at that age. You just never knew and she never seemed to be on a schedule.

Look at the NPS website as there are several historical places to visit along the rim. I think the first view coming from the east is the most dramtic. I forget the name of that one. Perhaps the reason I like it is because it has been the first thing I saw on my trips there. It is very poweful experience for a few seconds.

Early March can still see winter conditions at the South Rim. The North Rim will still be closed till Mid May.

I would not recommend hiking down into the canyon with the infant, even in a back pack. Call me over protected, but it's not something I would do.

I would bring a stroller because there are plenty of paths that you could walk along the rim and see the different overlooks in the Grand Canyon Village area. I'd also ride the free shuttle buses (kids love these) and get out at the different overlooks. http://www.nps.gov/grca/planyourvisit/shuttle-buses.htm

Utahtea

Bit dated but kids under 2 are free with most tour operators { Bus, Airplane or Helicopters} You also need to think about weather for anytime of the year. Right now, for instance, consider the best sun block on the market for the little tykes or adults.