Yes. The only statutory ground you cannot apply for a nonimmigrant waiver would be under a security risk to the U.S.
Normally, that would be submitted once you submit your application for the nonimmigrant visa.
No. Nothing in immigration law is ever guaranteed to be approved. It should be convincing and show you have been rehabilitated.
An INA 212(d)(3)(A) waiver is available for nonimmigrant visa applicants inadmissible under INA 212(a)(2)(B). Factors in considering whether to recommend a waiver include the nature and date of the offense, possible rehabilitation of the alien’s character, and the necessity for, or urgency of, the alien’s proposed trip to the United States.
When applying for a waiver at a US Port of Entry, your package should include evidence of your citizenship, why you are inadmissible, all documents showing rehabilitation, waiver forms and if you have it a legal brief arguing why you should be granted the waiver.