If I get the Enthoo Pro, will I be able to run nine case fans on it without modifications?

That's a lot of fans for a 650W PSU. The short answer is yes, you can use a lot of splitters on your SATA taps. It will be a little messy, but you could do it. There might be a total power problem on the 12V rail if you need a lot for GPUs- what are you running?

You might consider a larger PSU with more power taps.

With only one 970, you should be fine on power, but again you'll have to use quite a few splitters for all your fans. You can power 3 off of your motherboard, the rest will have to come right of the PSU (with no speed control).

So I did some detailed research...good news.

You'll need one of your PSU SATA power taps for your 3 drives (one cable that comes with the PSU can power up to 4 devices). You will have two PSU SATA power taps available. The PSU also comes with a cable to provide four 4-pin MOLEX heads from one SATA power tap.

Your motherboard has three 4-pin case fan connectors (for PWM or regular fans) and one 3-pin connector (for regular fan), all of which can be used for speed control (PWM fans are controllable down to 0 RPM, while voltage control can be used to control non-PWM fans down to about 30-50% rated RPM).

So, you can power up to four of your fans directly off of the motherboard. And you can power multiple fans off of the available PSU SATA taps, using something like this:

http://www.newegg.com/Product/Product.aspx?Item=N82E16812493026&cm_re=molex_fan_cable-_-12-493-026-_-Product

With two of the above-linked adaptors and your included cables, you should be able to power all of your fans (note that the ones powered directly off of the PSU will be running at 100% speed fulltime). There are versions of the above-linked adaptor that tap 5V instead of 12V such that your fans will be running at about half speed all of the time (instead of 100% fulltime).

Another option is the below product:

http://www.newegg.com/Product/Product.aspx?Item=N82E16812493026&cm_re=BFA-MSC-M33F12VKK-RP-_-12-493-026-_-Product

The above product will allow you to control speed of up to five *PWM* fans together (but not independently) from one motherboard case fan connector plus one MOLEX head (from PSU SATA power cable). This gives you many possibilities. For example, you could control speed independently of 3 fans from the motherboard, and then control 5 more together with the combination adaptor- one remaining fan would be powered directly from the PSU. Or you could power two of your fans directly from motherboard and then split up the remaining 7 onto two of the 5-fan adaptors above.

Hope this helps.


EDIT... Important: realize that your motherboard case fan connectors can each support up to 1A if they power a fan(s) directly. None of my above examples use splitters off of the motherboard, so you just need to make sure the fans aren't over 1A (unlikely). But if you do go another route and use splitters, watch the total power draw. The 5-fan combination adaptor I linked above doesn't have this constraint as it gets the PWM RPM signal from the motherboard but draws power from the PSU.

Is there any particular reason you're trying to load the case up completely with fans? I only ask because it's liable not to do much (diminishing returns) for the case cooling, adding to the complexity of the system etc. If you're running the windowed enthoo pro you'll probably want to leave out the psu cover (which is actually quite nice) for one of the bottom fans to have any effect. The other bottom fan might be able to fit in the middle of the lower hdd rack, if not it will have to come out. I added two 140mm noctua's to the top of my enthoo pro and honestly it's kind of overkill alongside the front 200mm and rear 140mm. I use a fan controller to turn all the fans down from full speed so it doesn't sound like a hurricane. Keeps everything nice and cool with an oc'd 4690k and hd 7850 (which I imagine puts out similar heat to the 970 since amd cards aren't known for running very cool).

I have a Enthoo Pro and I currently have one 200 mm in the front, three 140 mm (two on top one in the rear), and I plan to put two more 140mm on the bottom and the other on the top. You really shouldn't need to put a fan on the HDD rack because if you put them on the bottom rack (there's two) the 200mm will blow right over them. Also my case came with Hub for the fans that allows you to plug six fans into it and from what I've read this is comes with all cases on the Enthoo Pro. The hub only sends a reading of fan #1 to the motherboard however and whatever speed you tell it to run at is what speed they all run at (Fan #1 = #2-6 in speed).