1) Can Still take this feat if I have one level in DD?
2) if I all ready have this feat for say arcane dose it become draconic?
3) will DD level my other blood line if I have cross blooded archetype Ex: level one Orc blood line (touch of rage) can I select that instead of the dragon claws. Or strength of beast at 9th level.
1) Can [I] Still take this feat if I have one level in DD?Yes. I don't think there is a ruling against Eldritch Heritage functioning if you have a level in sorcerer. Just be aware that many of the bonuses among the bloodlines are enhancement bonuses, meaning they don't stack with each other or the belt/headbands. To put it differently: enhancement bonuses do not stack.
2) if I all ready have this feat for say arcane dose it become draconic?No, it remains as Arcane. However, DD counts as having levels in a draconic blooded sorcerer. So, if you have 2 levels in Dragon Disciple you are counted as having two levels in the draconic bloodline, due to Blood of Dragons.
3) will DD level my other blood line if I have cross blooded archetype Ex: level one Orc blood line (touch of rage) can I select that instead of the dragon claws. Or strength of beast at 9th level.
Think about Crossblooded as making a mutt bloodline that counts as both. A crossblooded Draconic Orcish sorcerer is technically neither Draconic nor Orcish, but instead both at the same time. You are making a unique bloodline that is allowed to cherry-pick what it wants from the two bloodlines.
So ifDraconic bloodline = 1
Orcish bloodline = 1
Crossblooded Draconic/Orcish bloodline = 1 instead of 2, since it is effectively the Draco-Orcish bloodline. Think of it as Paizo not wanting to spend countless extra pages and weeks fleshing out new bloodlines that are just combinations of the current official bloodlines.