To date, very little was mentioned on-screen (in canon) on how hyperdrive works.
It hadn't been used to go beyond the galaxy (or, at least no mention of that was made).
A lot of the outer rim of the Star Wars galaxy is also unexplored or otherwise remains unknown.
However, it was stated that in order for Hyperdrive to work, you'd need accurate star charts, otherwise you risk slamming into a star or a black hole (this makes little sense considering how large space actually is... and the distances between stars are usually humongous... but your chances of slamming into a star do increase if the galaxy is very small).
We also know little of how fast it actually is given that almost little is stated on how long it takes to get from one destination to the other and no information on the distances involved.
The Millenium Falcon was stated by Han Solo: She’ll make point five beyond the
speed of light.
What does point five beyond the speed of light mean in the context of Star Wars though?
1.5C? (that's way too slow to traverse huge distances in any appreciable amount of time even if the galaxy is a small one).
How big is the smallest galaxy?
The black hole is five times the mass of the one at the center of our Milky Way galaxy. It is inside one of the densest galaxies known to date -- the M60-UCD1 dwarf galaxy that crams 140 million stars within a diameter of about 300 light-years, which is only 1/500th of our galaxy's diameter.
For Hyperdrive to work on such a scale and being able to go from one end of the galaxy to the other in say 2 or 3 days.. the speed of the Hyperdrive would need to be about 42,946 times C (would need just about 2 and a half days to go from one end of the galaxy to the other).
So, if a galaxy is very small and is densely packed with stars like M60-UCD1, you'd probably have to be careful about exiting Hyperdrive (plus, gravitational fields from Stars might affect ships).
None of the expanded universe novels or technical manuals were ever considered to be canon by George Lucas or officials who made Star Wars before Disney took over.
And also, after Disney took over, only the things we saw on-screen (movies) and their novelizations have been generally accepted as part of canon (nothing however that would validate fan made up gigaton level firepower on ISD's part for example or existence of Hypermatter).
Mind you, my familiarity with Wars newest canon is a bit rusty, so there might have been some things mentioned since Disney took over that explains Hyperdrive better than what I'm familiar with.
Does Hyperdrive create wormholes, warp bubbles and whatnot?
Warp bubbles? Not so much - since they rely on usage of subspace in Trek, but little to no mention is given of subspace actually existing in Wars universe or that its being used as any type of medium for FTL or communications.
It doesn't seem like Hyperdrive generates wormholes... it looks similar to a tunnel which a starship uses to travel at FTL, so it might be similar to Slipstream... but it appears that unlike Slipstream, you need correct star charts for navigation.