Questions about Silverstone Sst-Gd09b

I can't say anything about the board - but an ATX form factor board (i.e. the "biggest" ones for home PCs) fits in. There are probably problems with the holes on an ssi ceb board - I wouldn't risk it. A GTX 970 of "normal" design fits in easily.

17cm is including the feet. I would like to sell my case because I have switched back to a tower. If you are interested, I will sell it used on Digitec.ch.

Yes you can simply install a Corsair H80i v2 (9.90cm) CPU wakü in this enclosure as space is provided for it?

(in 5.25'')