Strictly, speaking, caffeine is not addictive. However, consumers can become physically dependent, as evidenced by sluggishness, bad mood, and headaches when consumption is stopped.
Jessie puts a quarter in the jukebox at The Max but doesn't select a song. The jukebox plays just the song she wanted it to play anyway.
The jukebox at The Max plays an instrumental version of "I'm So Excited" by The Pointer Sisters. Most jukeboxes would not be stocked with an instrumental version of a popular song.
When Lisa and Kelly are supposedly singing at the Max for the record producer, there are multiple times that it's obvious they are just dancing and smiling, not actually singing.