As promised (if anyone reads this) I can now report from personal experience that all DSTE brand grip stuff works flawlessly with 9fps (EN-EL18 only) Btw, it’s an amazing sound to hear the camera shoot those 9fps, like a machine gun.
To fill the grip one has four options:
1. AA batteries (holder comes with the grip) no 9fps
2. EN-EL15(a) batteries (holder comes with the grip) no 9fps
3. EN-EL 18 (a or b): DSTE sells a battery with a battery compartiment cover attached to it. (Non separateable) That cover is also a charger and comes with a power cord and a car lighter cord. Gives you 9fps
4. EN-EL 18 (a or b): any generic or native Nikon battery will fit in, though one needs to buy a separate battery compartiment cover to keep the battery in place. I have a DSTE one, don’t know about other brands, though I suppose if they are properly copied they will do too. It is very easy to adapt the AA battery holder to function as cover. Just push an EN-EL18 in firmly, so that it slides into the contacts, measure the remaining space and cut the AA holder to size. And presto, there’s your DIY battery compartiment holder. Gives you 9fps
Although I would have preferred a magnesium alloy (like Nikon’s native grip) aftermarket grip, like I had for my D800 series, this one feels very sturdy and well made. No wiggling room between the camera and the grip, the look and feel are as one unit.
Last but not least: I could not find the battery/charger cover combo on Ebay or Amazon, but fortunately retailers in my country (NL) sold them. All the rest I purchased on Ebay in China and it arrived within two weeks.