We were there 5/15 - 5/22 on the Kudu trail overlooking the Sunset Savannah. This is the area that pretty much overlooks the new building under construction. We saw a handful of animals out on that savannah during the course of the week, but not nearly as many as we have in the past. There was no construction "noise" that I could hear from inside the room, but you could hear the humming of the machines when the balcony door was open.
We did, however, see plenty of animals in other viewing areas and on other savannah's. And since I had reserved a standard view room that was supposed to overlook the parking lot and bus stop, I was perfectly content where I was...it didn't matter to me that we had to go down the hall to see the animals. However, if I had PAID for a Savannah view and that was my view, I probably would have been a little disappointed...but it wouldn't have ruined my vacation! There's no telling what will be going on in September, but based on what the building looked like last month, I think they'll still be doing outside construction on Kidani - I'm not a contractor, but it didn't look like they'd be moving to the interior only by then.
But reserving a pool view room will pretty much guarantee you will be away from the construction since it is on the opposite side of the resort...and it is only a little bit more $$ than a standard view room. The restaurants are over on that side as well, so if you're in a pool view room, you really won't even need to go over to the "construction side" and you shouldn't be affected AT ALL.
Lat month was our 4th stay at AKL, and even with the construction next door, it was still fabulous. If you have any other specific questions, I'd be happy to help!