FanficRecs My Blood! I'm Bleedin'!
This fanfic is daaaark. Dark, dark, dark, dark, DARK. It's the darkest dark to ever dark. This is darker than a Darknut listening to darkwave on the dark side of the moon. This is Warp Darkmatter eating dark meat chicken with a side of After Dark whiskey.
It's kinda dark, is what I'm getting at.
Now, we all know that's not necessarily a bad thing. During certain times ANY story is going to be dark and hopeless (hopeless, by the way this story is NOT: One Piece's pervasive optimism is still strong in this story, even if it's not always obviously there). This story clings fairly closely to One Piece's original story: it hits the same beats, the Strawhats go to the same islands, mostly the same villains are fought, and mostly for the same reasons.
The difference this story hinges on is two-fold: the Strawhats took longer to rest up after fighting in Alabasta, and Luffy now has to fight twice as hard and make leaps in skill and power TWICE as absurd as in the original story. Fights are in general grittier, more personal, and more violent. Partially because of this, the Strawhats leave the islands they land on in considerably worse condition than they do in the original story, especially when they find trouble and bring it with them (coughDanMarcuscough). The attitudes of the people of the islands are different as well. Luffy seems to have lost a lot of the 'luck' that has carried him through the series since the beginning, and it shows in how he acts, and how the other characters treat him.
Now to the nit-picks: I don't particularly like Luffy's arc in this story. Much of his original bubblegum joyfulness is lost, and his fights are so much more visceral and intense that the sheer AWE you get when you see him pulling off an insane win in the original is dulled. This fic definitely suffers from Darkness Induced Audience Apathy to a degree, as well: so much just goes WRONG for the characters, and ever high is followed by an even lower low. That hope I mentioned before is colored also by very real despair. It's almost Attack on Titan-level despair-at-creeping-inevitability.
So do I recommend this fic? Not really, no. Unless you really desire to see a far-more textually-violent One Piece world (since much of the horror in One Piece is usually sub-textual), you might want to steer clear.
It's darker than Dark Truth Stout, man.
FanficRecs Epic story, BUT...
Lots of good moments in the story, definitely worth a read, yet there's a big 'but' there.
Firstly, the good, and there is a lot of good. It's well written, good characterisations, very detailed and there's clearly been a lot of effort put in to it. The action scenes alone are very intense. Overall, there are a lot of reasons why you should give it a chance.
BUT, there are also quite significant elements that could easily rub you the wrong way. It is a dark story, and it is getting even darker especially in the most recent arc. There's a lot of injuries in the story, and absolutely anyone can die. If you going to read, be prepared for that.
Also, there's a much more gritty texture compared to the typical happy go lucky feel of the fandom. Luffy dies, he loses his devil fruit, and it affects him. He becomes a lot more jaded, less forgiving, and gradually had to deal with that. There is a lot of character development in the story, even if that development isn't always in the right direction.
Still, the story is very emotional; there are absolute rollercoaster rides, even if the duration of the rollercoaster does get tiresome in parts. It challenges readers and defies typical conventions in one piece fanfiction. Some people can enjoy that, others can't.
As for the story, well, there's a lot of it. It's a very slow pace, but detailed. Each arc is pretty much a novel by itself. Skypiea must last around 200000 words, and it seems like Water 7 will end up the same. Don't expect the story to reach the timeskip any time soon.
Also, the harem. Again, it can understandably put people off. The romance is pretty slow for the most part. Honestly, a lot of the romance is awkward and distracting from the main story, but to it's credit all of characters are well characterised. It was an attempt at creating a 'realistic' harem story - it didn't really hit it's target, but it tried.
The best description I can think of is that Nine Minutes is a pretty epic attempt at a gritty retelling of One Piece. There's lots of reasons why it could irritate you, but there's plenty of good in there too and it probably doesn't deserve dismissing altogether.
Overall, I'd probably recommend just giving it a try; it's the type of story you could either hate it or really enjoy it, but you figure out which one pretty quickly.