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