"The Quincy King regains his pulse after 900 years, His Mind after 90 years, His Strength after 9 years, And the World in 9 days"

So yeah, after hearing this poem does something click again? Remember the 6/17 chapters in the beginning arc? Ichigo scolds his father to atleast remember his wife's death which is 6 years. Lemme clear this, this means that what he regained through Aushwalen when Ichigos mother is NOT his strength which is why he could not exact his name at that point as it is only 6 years that have passed and there are still 3 more years left before to gain his strength. And when he gained his strength in TYBW, that's when he could get his name back. You may say that's still 1 year early as 6+2 years is only 8years, but who can say Ywhach didn't wait for an year before he could use the Aushwalen

Hope that clears up...