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