Citizenship is kind of a weird topic in Traveller, since there's no real definition of an "Imperial Citizen" in the rulebooks.
IMTU, any sophont that is from a world within Imperial borders is considered an Imperial Citizen. After all, residents of any Imperial world benefit from Imperial forces/policies (such as receiving naval protection). In addition, the economy of that world benefits the Imperium through trade, so all of the workers and facilities of that world help the Imperium.
Imperial Citizenship is just a blanket covering the residents of the Imperium (IMTU). It's not like citizens get to vote for leaders, since they are nobility appointed through the Emperor. So there's no reason not to extend citizenship to any resident of an Imperial world.
Of course, exceptions can exist. Interdicted worlds, or those actively resisting Imperial control, might have questions regarding the status of their citizens.
IMTU, any sophont that is from a world within Imperial borders is considered an Imperial Citizen. After all, residents of any Imperial world benefit from Imperial forces/policies (such as receiving naval protection). In addition, the economy of that world benefits the Imperium through trade, so all of the workers and facilities of that world help the Imperium.
Imperial Citizenship is just a blanket covering the residents of the Imperium (IMTU). It's not like citizens get to vote for leaders, since they are nobility appointed through the Emperor. So there's no reason not to extend citizenship to any resident of an Imperial world.
Of course, exceptions can exist. Interdicted worlds, or those actively resisting Imperial control, might have questions regarding the status of their citizens.