Bottling yeast = bottle bombs?

[OdinsBrew]

here's the main question: I've heard of add yeast at bottling. Pitching a packet of dry notthinghams. Why does this not create bottle bombs?

My story:
I've got a 9.3%abv brew made with WL belgian yeast. This stuff takes forever to carbonate in bottle. If I pitch in some nottinghams dry yeast into the bottling bucket (or a day or two before bottling), will that make it carb faster? And if so, why does this not create bottle bombs?

 

[Revvy]

It's not more yeast that causes bottle bombs, it's adding too much sugar, or adding sugar to too much unfermentable sugar already present (like bottling too soon.) The yeast will only consume what sugar is available to it, regardless of the amount of yeast you add. You can add a pound of yeast and if there's only 5 ounces of sugar to be eaten, then once it's gone the yeast will not have anything to eat.

 

[fineexampl]

If i understand it correctly, when you correctly bottle anything you're only going to have enough sugars eaten by the yeast that will effectively keep things at safe levels.

For instance, once you brew and ferment, you wait until all of the fermentable sugars are converted to alcohol. Then you would add a measured amount of sugar so that the yeast will convert all of that sugar to CO2 and a marginal amount of alcohol and pressurizing the vessel/bottle. Once the sugar is gone, there's nothing left to eat and so the yeast goes dormant.

I know that doesn't answer the 2nd question, but i'm sure someone else will pipe in with a better understanding of yeast strains and their speeds.