To unlock Practice mode, get Kitty Bling in Story mode.
To unlock the White Room, score 10,000 points in Practice mode.
Score the following amounts of points in Practice mode to unlock the corresponding All-Stars:
POINTS - ALL-STAR
40 points - Strike the soccer player
400 points - Ace the tennis player
1600 points - Clutch the baseball player
4000 points - Slice the golf player
10000 points - Snappy the football player