Ok so, one question: can you compare Hubble to Action directe?
One answer: no...
Action directe is 16 moves long.
Hubble is four.
(Just counting the hard ones)
Every move out of the four in Hubble is harder then any of the Action directe moves.
Hubble really feels more like a boulder, whereas Action directe is a route
One has got monos the other one underclings.

Which is harder to climb?
Depends who you are...

If you are for example Alex Megos
Then it depends I would say on conditions, general fitness of the day, temperature...
If everything is perfect I would say I don't have big trouble climbing Hubble multiple times a day.

Sounds like they are more or less equally difficult but quite different?
I really think you can't tell.
They are so different and for some people they are probably miles apart from each other in terms of difficulty.
I climbed three routes that were orginally graded 8c+'s at that crag [Raven Tor] now, Hubble, Kabaah and Evolution. 

I definitely struggled the most with Kabaah, although I still think its 8c+.

So...about Hubble, you're not saying it's not 9a, neither that it is?
For some people it is, for some it's not.
For some it's impossible, although they can climb 9a.