Snake's abilities as a blind man are a little fantastical, and another character does cry ableism at one point (and somewhat fairly so, though the game does acknowledge that). Otherwise, no.
None of the characters are really objectified outright, but Lotus's attire is pretty questionable (for reference: https://static.wikia.nocookie.net/ninehourspersonsdoors/images/4/47/Lotus.png/revision/latest?cb=20150120112721)
It depends on how you define 'abuse'. (Spoilers from here on out) Zero is revealed to have previously been a victim of the Nonary Games. In material outside of the games, another main villain is revealed to have suffered the same.
Most of the Nonary Game participants were presumably brought on-board after being knocked out by anesthetic (the main character's drugging is shown on-screen). In addition, multiple characters are injected with anesthetic at points during the main story, as is a separate character during a bonus ending in the iOS port.
A character drowns in one of the endings (the exact cause of death is a bit unclear, as they are also stabbed, but it is likely a combination of both).
Not reasonably applicable in the DS version, as none of the characters are "played" by anyone. In any case, it may be worth noting that Snake, a blind man, is played by a non-blind voice actor in the 2017 remake.
Some characters are restrained at some points in the story, mostly via chokeholds. The most notable instance occurs in one of the endings, when a character is physically restrained during an emotional outburst.
Snake, the only character who is outright part of a minority (blind), is depicted accurately enough. Lotus's design is questionable, though: https://static.wikia.nocookie.net/ninehourspersonsdoors/images/4/47/Lotus.png/revision/latest?cb=20150120112721
The protagonist (and presumably all the other characters) were kidnapped prior to the start of the game in order to participate. Junpei's kidnapping is shown in a flashback.
Given the story revolves around being trapped in rooms inside a slowly sinking ship, the whole game can have a claustrophobic feeling, on top of scenes where characters are stuck on even smaller spaces and desperate to escape.
As with many multiple choice games, there are many bad endings that can be achieved by making "incorrect" choices, but the actual ending of the game is a happy one.
No nuclear explosions, but a main plot point of the game is that every character has a bomb inside their bodies that will go off if they disobey the rules. Some characters are blown up.
Usually minimally shown and mostly described (in visceral detail. Skip past the descriptions whenever someone is blown up if you're squeamish.) In some of the bad endings, characters are shown lying dead in pools of blood.
In one ending of the game, the main character drowns. This could be an upsetting scene for those triggered by drowning, so take caution if you see a submarine.