Here is the full list of all 85 Final Fantasy IX achievements. It takes around 80-100 hours to unlock all of the achievements on Windows.
Defeat 10000 enemies.
Win 100 Tetra Master matches. (Certain NPCs can be re-challenged to increase your win count after progressing through the game.)
Receive certification as a Rank S Treasure Hunter.
Jump rope 1000 times without tripping and obtain King of Jump Rope.
Raise your chocobo's beak level to 99.
Defeat 1000 enemies.
Receive 30 back attacks.
Obtain Excalibur II.
Beat the Nero Brothers' shuffling game nine times in a row.
Obtain Athlete Queen.
Obtain Madain's Ring via mining.
Jump rope 100 times without tripping.
View 79 Active Time Events.
Have a single character affected by all status ailments. (both beneficial and detrimental).
Correctly answer all the questions in Ragtime Mouse's pop quiz.
Purchase all items available from Stiltzkin.
Obtain 4 moonstones.
Obtain the Gastro Fork.
Successfully catch 99 frogs.
Defeat Ozma.
Acquire all available support abilities.
Attain level 99 with at least one character.
Play the blackjack minigame.
Complete FINAL FANTASY IX.
Summon the eidolon Ark.
Defeat Lich, the Guardian of Earth.
Obtain the Mace of Zeus.
Defeat Kraken, the Guardian of Water.
Defeat Tiamat, the Guardian of Wind.
Obtain the Rune Claws.
Obtain the Angel Flute.
Defeat Maliris, the Guardian of Fire.
Obtain the Tower.
Obtain Kain's Lance.
Use Blue Magic spells 100 times.
Use White Magic spells 200 times.
Summon Eidolons 50 times.
Summon the eidolon Madeen.
Summon the eidolon Phoenix.
Win 10 items at the Treno Auction House.
Uncover the secret of the Eidolon Wall.
Visit every beach in Gaia.
Obtain the sacred blade Excalibur.
Defeat Behemoth in the Treno weapon shop using Dagger.
Summon the eidolon Odin.
Obtain the Ultima Weapon.
Repair the machine at Mognet Central.
Obtain a bottle of Superslick.
Obtain the Hammer.
Gain the favor of all friendly enemies.
Activate the Rebirth Flame ability when all party members are incapacitated.
Summon the eidolon Bahamut.
Summon the eidolon Leviathan.
Summon the eidolon Atomos.
Locate all hidden treasures on the world map.
Obtain the complete set of Genji armor.
Obtain the Whale Whisker.
Obtain the Tiger Racket.
Synthesize 30 items.
Receive 10 rewards from Queen Stella.
Obtain an airship.
Summon the eidolon Ifrit.
Summon the eidolon Shiva.
Summon the eidolon Carbuncle.
Form a party with Quina Quen and three female characters.
Form a party with four male characters.
Enter trance 50 times.
Obtain a miniature copy of the Prima Vista.
Receive a Very Good Omen from a color fortune.
Use Black Magic spells 100 times.
Summon the eidolon Fenrir.
Free Kuppo from a wall in Fossil Roo.
Summon the eidolon Ramuh.
Synthesize 10 items.
Use the Defend command 50 times.
Use the Steal command 50 times.
Guide all the residents of Cleyra to safety.
Defeat 100 enemies.
Cause Moguo to have a tantrum.
Successfully catch a golden frog.
Win with Vivi during the Festival of the Hunt.
Win 10 Tetra Master matches.(Certain NPCs can be re-challenged to increase your win count after progressing through the game.)
Enter Trance for the first time.
Have the nobles demand an encore.
Win a Tetra Master match.