The declaration of the rights and grievances of the colonies drafted by the nine colonies represented at the stamp act congress demonstrated that

The declaration of the rights and grievances of the colonies drafted by the nine colonies represented at the stamp act congress demonstrated that: the different colonies had to work together for a common goal
Even though each of those nine colonies have different agendas on their hand, they're all suffering under the rule of the British Empire. So for the purpose of getting them out of the country, the nine colonies united as one for the revolutionary war