I have never hit the 909 driver but the 915d3 is not to unforgiving if you hit the driver solidly. If your hitting 255-270 you probably have decent contact so if the d3 offers the ball flight you like over the d2 go with it. The D3 still has weight in back so it still provides that touch of forgiveness. Although the head is slightly smaller which does bring the CG closer to the front vs the D2 and gives it lower spin and launch. The D3 is designed to let you play both the penetrating and high flying shots on your control.

Getting fit for a 915 may be difficult as they won't have all the available demo parts, but around me I see quite a few new still on the rack with various shafts and lofts and there are a handful in the pre owned section with additional shafts to try out. I would definitely look into getting a hold of as many combinations to find your match.

I played the 910D3 and moved to the 915D2 and the accuracy of the larger head was incredible. Also I played my 910 at a 9.5 and am now playing my 915 at an 11*. You hit the ball farther than I do and I imagine you are much younger than I. At 70, I am in the 230-240 range and am comfortable with that, and according to my fitter, I should be happy. But my accuracy is great. What you might consider is the new 917D2s. With the right shaft you might be able to take you drives to another level with great accuracy. The Titleist Thursdays should be kicking off, I believe in May and I would recommend going to one of those and seeing one of the Titleist fitting specialist and get a professional fit. It is free. Take your current driver with you and see how the new 917D2 compares with you 2009 driver and I think you will then know the direction you need to go. I really like the performance of my 915 because it is really dialed in for my game, but am going to a fitting in May and compare the 917D2 for reassurance. I strongly recommend that you consider the 917 which is the top dog of Titleist drivers at this time. Getting a correct fit with the right shaft and head is not a waste of time and with the Titleist Thursday, it only takes 45 minutes and it costs you nothing. With the new drivers, more loft may be needed. Less spin more distance.

For some of the reasons you cited (primarily the great price), I just retired my trusty 909D3 (8.5 deg stiff Diamana S+ Blue 60) after recently picking up the 915D3 (8.5 deg stiff Diamana D+ White 70). With the default surefit hosel setting (A1) on my new 915D3, my ball flight is a little lower than before, mostly thanks to the different Diamana shaft, which is what I had hoped for. My accuracy seems about the same -- certainly no worse. I've also picked up a comfortable 5-10 yards. My sample size is admittedly small given we are coming off of winter in Chicago and I haven't had the 915D3 for more than a few months.

There's no substitute for testing and fitting, and that's where I'd start. However, I'd estimate you will pick up at least 5 yards with the 915 and your accuracy should be comparable to that of your 909D2, regardless of which head you choose. Just a guess but I think you can make the transition from the D2 to D3 head without much fanfare. With a number of variables at your disposal like the D2 vs D3 head, various shaft options, and surefit hosel settings, I'd bet you can attain your desired ball flight with added distance by throwing one of the 915s in your bag.

I had the same shaft in my 909d2 and used it for a long time. I let my friend borrow it so he could try it and I get it back in two pieces. I bought a 915d3 and absolutely love it. For me and my swing it is the best driver I have hit. In going from the 909 to the 915 my distance increased a little bit and I am much more accurate with the driver. With that being said, everyone is different and the best thing to do is test options out and get fitted like a lot of the people above said.

I just switched from the exact same driver. 909 D2, 9.5* with the VooDoo shaft, to a 915 D2 with the Fujikara Speeder 757 shaft, S-flex.
Unfortunately we just got dumped with snow and I have only hit maybe a dozen ball so far.
But I am totally looking forward to some increased distance, when the snow melts.

Well I tried a 915 D2 today.
9.5 degree with the Diamana White 70 Stiff shaft:
1. My goodness it's loud! Used it a driving range bay. It echoed!
Almost embarrassing. I the D3 is louder I'll need ear protectors.
2. Easy to hit. All shots (about 20) were solid. The off centre strikes were all forgiven and achieved good distance.
3. Felt long. Difficult to judge as I was hitting into a gale. I forgot the 909 so had no comparison. All looked to be about 245/250, all fly as there was no run out there.
4. Looked really good at address. Had it in the standard setting (A1 I think) so looked a bit open when resting on the ground. Thing is, with this club I felt confident enough to hover it behind the ball.

Taking on to the course on Saturday so will let you know how I go.

So I hit the course with the 9.5 degree with the Diamana White 70 Stiff shaft.
It's a demo club and I didn't pick up until the end of the round that the loft had been reduced to 8.75. Probably due to the fact that I was not having any problems getting it airborne.
The first tee shot was awesome (if I say so myself) and I thought that I'd be buying one at the end of the round.
However of the remaining 9 holes that driver is used, only one felt that I'd really connected. The others we a bit weak, saying that, my all were all but as long as one of my playing partners and longer than the other two.
I think that the benefit I will get will be improved forgiveness and distance with a poor shot, rather than all of a sudden being 'huge' off the tee.
A couple of more tests required.I have still not hit 909 and 915 back to back yet, that would appear to be a must on my next trip out.