I really really hope it will be much better than MP8! pweeese!

Well, on with it:

My Charas:

Mario
Luigi
Peach
Daisy
Wario
Waluigi
Yoshi
Birdo
Toad
Toadette
Boo
Dry Bones
DK
Diddy Kong

Unlockable:

Shy Guy
Rosalina
Funky Kong
Toadsworth
Koopa Troopa

Stages:

Luma's Observatory
Monty's Mine
Cheep Cheep's Pool
Petey Piranha's Rain Forest
Bowser's Carnival

Items: Orbs (again, they're so much better than candy)

Some Orb Ideas:

Baby Orb: turns character into baby version of himself/herself/itself

Characters:
Same as the ones from Mario Party 8.

Unlockable:
Diddy Kong

Boards:
Princess Peach's Castle (Takes place on the inside and on the top of the castle from Super Mario 64)
Luigi's Mansion (A similar board to King Boo's Haunted Hideaway)
Yoshi's Island (A small island with many spaces though)
Daisy's Daisy (Takes place on a giant daisy)
Bowser's Magma Madness (Needs to be unlocked)

Past Boards:
Goomba's Booty Boardwalk
Shy Guy's Perplex Express
Koopa's Tycoon Town

Items: Candy. (All candies return a long with newer candies)

Past Mini-Games: (When it is a 4-player mini-game, there is a random chance of it being a past mini-game instead)

In the Nick of Time
Shake it Up
Treacherous Tightrope
Speedy Graffiti
Lava or Leave 'Em

i think they should have newer charters and the top 100 games from previos pario parties.
also they should have solo mode like it was in mario marty 3. that was good as

the playable characters should be

unlocked from start
mario
luigi
peach
daisy
yoshi
wario
waluigi
birdo
hammer bro
blooper
toad
toadette
boo

you can unlock

petey pirahna (super mario sunshine)
pauline (march of the minis)
rosalina (super mario sunshine)
professer e gadd (luigis mansion)

rosalina is from super mario galaxy

Well i have a few suggestions for MARIO PARTY 9 for Nintendo.

first n formost, they should have not only NEW party boards, but Retro boards, from old mario party games...

like this...
Peaches Birthday Cake (MP1)
Space Land (MP2)
Deep Bloober Sea (MP3)
Koopa's Seaside Soiree (MP4)
Toadette's Music Room (MPDS)

not only with retro boards they should have 50 new minigames, along with 50 retro games.

a few like
Bumper balls
Face Lift
Book It

i mean there are tons to choose from

the characters? there should be 12, with 4 unlockables.
Mario
Luigi
Peach
Daisy
Yoshi
Toad
Wario
Waluigi
DK (Bring 'im back)
Toadette
Blooper
Hammer Bro
**********
Koopa Troopa
Shy Guy
Goomba
Dixie Kong (meh not my first choice)

Well, always hope for da best.

The smartest thing that they should do, going with the idea of bringing back retro games, they should have polls for each of the MP1-3 games. It would have the minigames with snapshots and people would choose their ten favorite or something from each game.

Maybe do the same for boards.

petey should be in

Mario Party 9 ideas

For Gamecube,DS,Wii

Modes:
Party House(Party Mode)
Story Book(Story Mode)
Duel Stadium(Duel Mode)
Solo Boat(Solo Mode)
Mini Game Arcade(Mini Game Mode)
Puzzle Maze(Puzzle Mode)
Shroom Mall(Store Mode)
Galaxy Gallery(Gallery Mode)
Control Room(Control Mode)

New Modes:
Trio Towers(Trio Mode,Note:It's like Duel Stadium but with an extra compeetor.)
World of Wi Fi(Wi Fi Mode)

Characters:
Mario
Luigi
Peach
Daisy
Yoshi
Birdo
Wario
Waluigi
Toad
Toadette
Boo
Dry Bones
Blooper
Hammer Bro.

New Characters:
Koopa Kid(Unlocked if the player plays Story Book 3 times.)
Bowser Jr.(Unlocked if the player plays Duel Stadium 3 times with Koopa Kid.)
Diddy Kong(Unlocked if the player plays Solo Boat 3 times.)
Dixie King(Unlocked if the player plays Trio Towers 3 times with Diddy Kong.)

Items:
Orbs and Hexes returns

New Orbs:
Silver Mushroom Orb(Rolls numbers 11-20.Note:somebody else thought of this idea,I just got inspired by this.)
King Mushroom Orb(Rolls numbers 21-30)
Free Star Orb(Use the orb to get a free star.)

New Hexes:
Vacuum Hex(Steals all coins.)
Lightning Hex(Steals all coins.)
Warp Pipe Hex(Warps you to a random space.)

Boards

Nitro Boards:
Chocolate Mall(Find the star and buy it for 20 coins.)
Cake Towers(Race to the top of Cake Towers to buy a star for 20 coins.)
Shroom Hotel(It's a maze so choose 2 random elevators,1 random hallway.If that hallway you chose ends in a star space,you get a star,if it ends with a warp pipe,you don't get a star.)
Castle Garden(There are 3 magical flowers.1 hides a star,1 hides 30 coins,1 hides a King Mushroom Orb.Pay 10 coins to open a flower,it might be star.)
Chain Chomp Land(You start with 5 stars.Race to a random Chain Chomp and pay coins to stomp people to steal stars.
Regular Dice 10 coins
Silver Mushroom Dice 20 coins
King Mushroom Dice 30 coins)
Cookie World(Buy a cookie shop to get a star.If another person buys that cookie shop,they get 1 star and steal your star so that makes 2 stars.)
Bowser's Castle(Find the star and buy it for 20 coins.But beware Bowser,he can steal a star in a random turn.)
DK's Jungle Pathway(Race to Donkey Kong to get many stars as you want,as long as you have enough coins.

Retro Boards:
Mario's Rainbow Castle(Find the star and buy it for 20 coins.)
Space Land(Find the star and buy it for 20 coins.Don't get pass Koopa Kid,you will lose 5 coins.)
Chilly Waters(Find the star and buy it for 20 coins.)
Toad's Midway Madness(Find the star and buy it for 20 coins.)
Sweat Dream(Find the star and buy it for 20 coins.)
Snowflake Lake(You start with 5 stars.Race to a random Chain Chomp and pay coins to stomp people to steal stars.
1 Dice 10 coins
2 Dices 20 coins
3 Dices 30 coins)
Neon Heights(There are 3 magical chests.1 hides a star,1 hides 10 coins,1 hides a Bomb-omb.Pay 10 coins to open a chest,it might be star.)
Perplex Express(Race to Shy Guy and pay him 10 coins for a star.)

Mini Games:

Types of Mini Games(Note:If you step on a ?,Miracle,Duel,and Friend Space,it will stay green.)
vs. 4
2 vs. 2
3 vs. 4
Battle

New types of Mini Games
vs. 3
2 vs. 1
2 vs. 1 vs. 1

50 New Minigames and 50 Old Minigames.

Those are my ideas.

Whoops,I ment 3 vs. 1,not 3 vs. 4.

Sorry,I made a mistake at Lightning Hex.Lightning Hex(Steals all stars.)