Both are more than sensitive enough for what you need. The difference is how they drift/ fish different type/sizes of water. The longer rod lets you keep less line in of the water which makes it easier to get a good drift. The extra length makes it easier to mend you line in the water which improves the drift and it's depth in the water. Longer rods make a decent float rod also. The longer rod fishes spinner/spoons more effectively for all the reasons above. Longer rods fish bigger rivers better, and still do well in smaller waters.
Length in a well designed rod adds sensitivity, but a lighter rod like the shorter rod also adds sensitivity due to the difference in weight. The shorter rod also feels a bit more balanced in the hand. Longer rods aren't as much fun in close quaters once the fish is on. The combo of steep banks, small waters, or brush, and fishing by yourself is not near as fun with the long rod when the fish is hooked and near the bank, but it can be done.

Personally I believe there is a length at which, once exceeded, a rod's sensitivity decreases as it gets longer. That magic number for me is 9 ft. Don't get me wrong, there are 10.5 ft. rods out there that are plenty sensitive...just not AS sensitive as the same rod in a 9 ft. version. You have to balance what you plan to do with the rod, and your preferences, with the sensitivity factor. If you want to drift fish big water, and are chasing big fish, a long rod is probably worth considering, and worth the slight decrease in sensitivity you may experience. This is all assuming you are comparing like materials (e.g. an XMG against another XMG).

All personal opinion here, based on my experience. I agree that the lighter the weight of the rod, the more sensitive. I also agree with the need for a well balanced rod. You can have the most sensitive rod available and if it is not well balanced it will feel like a slug in your hand.

At the end of the day, you should go with the length that is going to give you the most confidence and also the one that is most enjoyable to fish with. The materials in the high-end rods available today are so advanced that I don't think the difference in sensitivity between a "long" rod and a "short" rod are going to cost you any hookups or bite detections. My $.02.

Caught my first winter steelhead yesterday on my new xmg EXC92M the bite was so light it was incredible the tipp of my rod didnt realy move at all but I felt the bite through the rod man these rods are more sensitive than I thought. It was a pretty big steelhead for the kalama river she was 11lbs 11oz and 32.5 inches long, the rod hads perfect power for the winter fish we have there so I can say that this is the best drift rod I have ever fished bar none I cant wait to try out my new EXS96L for summers and maybe even some winter fish too! Thanks agin for the advice I really appreciate it!

I think you made an excellent choice. I use the 10 ft version of the same rod. For your length I still use my custom Sage 290.