Sort of kind of, for some things.
Safe Passage
doesn't directly protect planeswalkers, so if a creature is attacking your planeswalker,
Safe Passage
won't stop the combat damage, because the creature is dealing damage directly to the unprotected planeswalker.
However,
Safe Passage
will be able to prevent (most)
noncombat damage (damage from spells or abilities), due to the weird way the game handles damaging planeswalkers with spells or abilities.
This requires a bit of history so that it makes sense, so hopefully this won't bore you to tears.
Planeswalkers weren't around for the first ten-plus years of the game's history, and in that time, a
lot of cards were printed that could deal damage to things or otherwise affect damage in some way. And every single one of them talked about damage to a "creature" and/or "player", because those were the only things around that could be dealt damage.
Then planeswalkers came along, and all of those damage-related cards suddenly presented a problem. Wizards wanted cards like
Lightning Bolt
to be able to hit planeswalkers and wanted cards like
Mending Hands
to be able to stop them, but as printed they couldn't do that, because planeswalkers are neither creatures nor players. So Wizards had a choice. They could either A) do nothing and have all of these old cards just not work with planeswalkers--which was crazy and unacceptable--or B) issue errata to
thousands of damage-related cards to have them work with planeswalkers properly--which would be a headache for players to remember and similarly unacceptable. So Wizards chose option C): put together a rules workaround so that everything worked pretty much the way it should without issuing errata.
The workaround they chose was that if something you control would deal noncombat damage to one of your opponents, you could choose to redirect that damage to one of their planeswalkers instead. This means that what you're
really doing when you say "I
Shock
your
Jace
" is that you're targeting your opponent with the Shock and then redirecting the damage to Jace.
This is where
Safe Passage
comes in. Since the damage is supposedly directed at the player first, you can have
Safe Passage
kick in and prevents the damage before your opponent can choose to redirect it.
The only kinds of noncombat damage that
Safe Passage
won't help against are cards like
Magmaquake
which say they deal the damage to the planeswalkers directly, since in that case there's no redirect involved.