3.9 Grammatically, the sentence could read "Lord of the promise is not slow." (technically, the word "promise" is in the genitive; this verb can take a genitive object, but it could also be a genitive not connected with the verb but instead with the noun that precedes it.)
The word used in the phrase "all to come to repentence" is "choore-oo." This verb comes from the word for space/region/place (As in the whole Judean Countryside came out to visit him). More literally, thus, this reads "God has room for all to come to repentence."
3.10 A Greek note -- the idea of the cosmos being consumed in a fire is a strong idea in Greek mythology and even stocism.
3.11 The word here for piety is "eusebeia." This word is not used in the Gospels or the Pauline core. Interestingly, Peter does use this word in Acts when he says to the people -- you think we did this of our own piety?? (3:12) (And the ansewr is no!)
3.12 The word translated hastening is "speud-oo," which can also mean "strive for."