Depending the Era, it is possible that the Padavan is a multiclassing Jedi, so basically it can be at level 6/1 anything/Jedi...
There are also some rules for Padawans in the Jedi Academy sourcebook that we could look at using, if the Padawan player doesn't want to multiclass. They're intended for NPCs, but could work ok for a PC.
Paraphrasing:
- While the Padawan is within 12 squares of their master, they add their master's heroic level to all of their defense.
- When the Padawan takes damage that would drop them to 0 HP and exceed their damage threshold, they're just knocked out instead of being killed.
- While adjacent to their master, the Padawan can redirect any attack made against them onto their master as a reaction (if the master is willing).
- Instead of taking a cut of the party's XP, the Padawan just gains as much XP as their master.
- Whenever the Padawan levels up, their master gains the 24-hour bonus from the Education destiny.
The Padawan is technically supposed to be a non-heroic character until they finish their training, but I don't see any reason those rules wouldn't work with heroic classes instead.
The downside is that the Padawan is still going to be relatively weak compared to everyone else under these rules - they're expecting to be doing things like flanking and assisting with attack and skill checks, rather than providing damage output and so on in their own right. Makes sense thematically, but might not be satisfying to play.