I keep getting Master Vampires ambushing me as soon as I leave Dragonreach. I've yet to start the DG Questline. So for those who say Vampires don't attack before the questline starts or before level 10 is either lying or lucky.

Anyhow can I wait inside Dragonreach till morning so they won't attack? Cause I'm about to uninstall this add-on and shove it where the sun don't shine to Bethesda.

You need to change what spawns somehow. I would suggest: waiting or going out onto the porch and then out the front door. Either of these actions can reset the spawn code.

Get some help, call a dragon or use the guards

vampires don't attack walled cities specifically before lvl 10, unless bugged

Wild encounters are still fully possible.

Not entirely correct. 10 is the level at which Durak will come looking for you. But you can begin the first quest at any level. And once you begin the first quest the vampire attacks begin.

Scary.

what do you mean by once you begin the first quest ? if you don't go in the fort, is there attacks ?

Yes, the attacks start at lv. 8 regardless of whether or not you start the quest.

Do they focus on you or are they attacking the town in general? If their focused on you then you can lead them to the guards barracks just around the left corner ( when leaving Dragonsreach ) thus giving you some much needed back up from the sounds of it. You don't have a save file from before you got pinned in do you ? If so load from there and see if it happens again other wise your stuck fighting your way out of it.