Did Gandalf know that the nine had risen or not?

Question

In Chapter 1, "Many Meetings", of The Fellowship of the Ring the following exchange occurs:

"Then you knew of the Riders already - before I [Frodo] met them?"

"Yes, I [Gandalf] knew of them. Indeed I spoke of them once to you; for the Black Riders are the Ringwraiths, the Nine Servants of the Lord of the Rings. But I did not know that they had arisen again or I should have fled with you at once. I heard news of them only after I left you in June; but that story must wait. For the moment we have been saved from disaster, by Aragorn."

Here Gandalf said that he was not aware that The Nine had risen, however, in The Hobbit extended movies, we get scenes where Gandalf indeed discovers that they've left their tombs. Is there anything in the literature the reinforces that they had risen at the time of the Hobbit or is this some creative freedom that Jackson treated himself to when they made the movies?

Answer 1

Gandalf is first made aware of the Nine in June of T.A. 3018

While investigating some danger that Gandalf had forebode, he chanced upon a member of his Order Radagast. Radagast had journeyed for Rosgobel on the borders of Mirkwood to find Gandalf to provide him of information that the nine were abroad again.

At the end of June... I... journeyed along the Greenway; and not far from Bree I came upon a traveller sitting on a bank beside the road... It was Radagast the Brown....

"Gandalf!" he cried. "I was seeking you."....

"[What] do you want with me? It must be pressing. You were never a traveller, unless driven by great need."

"I have an urgent errand," he said. "My news is evil." Then he looked about him, as if the hedges might have ears. "Nazgûl," he whispered. "The Nine are abroad again. They have crossed the River secretly and are moving westward. They have taken the guise of riders in black."
_{The Fellowship of the Ring, Book 2, Chapter II, The Council of Elrond}

While this doesn't conclusively provide evidence that Gandalf had not found this out in The Hobbit, all the details in "The Council of Elrond" about the White Council expelling Sauron from Dol Guldur make no mention of the Nine.

Some here will remember that many years ago I myself dared to pass the doors of the Necromancer in Dol Guldur ... and found thus that ... he was none other than Sauron... Some, too, will remember also that Saruman dissuaded us from open deeds against him...
_ibid.

I ... persuaded the Council to attack Dol Guldur first, before he attacked Lórien. We did, and Sauron fled.
_{Unfinished Tales, Part 3, Chapter 3, The Quest of Erebor: Appendix}

What remains unclear, however, is whether Gandalf had knowledge the Nazgûl had resurfaced but thought they remained in Minas Ithil (Minas Morgul), or whether he had no knowledge of their resurfacing at all. However, from the following extract of the Council of Elrond, Gandalf seems to suggest that they'd known the Nine had taken Minas Ithil and were residing there:

But we were too late, as Elrond foresaw. Sauron also had watched us, and had long prepared against our stroke, governing Mordor from afar through Minas Morgul, where his Nine servants dwelt, until all was ready. Then he gave way before us, but only feigned to flee, and soon after came to the Dark Tower and openly declared himself.
_{The Fellowship of the Ring, Book 2, Chapter II, The Council of Elrond}

Answer 2

The Nine were in Mordor whilst Sauron was in Dol Guldur. Sauron was driven forth from Dol Guldur by the White Council during the Hobbit (which is why Gandalf doesn't accompany the party through Mirkwood). The Ringwraiths and others had been preparing for his return to Mordor.

When Gandalf tells Frodo about the Ring, he doesn't know about the Ringwraiths but suspects:

Nine he gave to Mortal Men, proud and great, and so ensnared them. Long ago they fell under the dominion of the One, and they became Ringwraiths, shadows under his great Shadow, his most terrible servants. Long ago. It is many a year since the Nine walked abroad. Yet who knows? As the Shadow grows once more, they too may walk again.

It seems fairly clear from discussions in the Council of Elrond that it's the capture and interrogation of Gollum, sometime after the events of the Hobbit, that has prompted Sauron to use the Ringwraiths in pursuit of the ring.

"I have an urgent errand," he [Radagast] said. "My news is evil." Then he looked about him, as if the hedges might have ears. "Nazgûl," he whispered. "The Nine are abroad again. They have crossed the River secretly and are moving westward. They have taken the guise of riders in black."

I knew then what I had dreaded without knowing it.

"The Enemy must have some great need or purpose," said Radagast; "but what it is that makes him look to these distant and desolate parts, I cannot guess."

"What do you mean?" said I.

"I have been told that wherever they go the Riders ask for news of a land called Shire."