bind a survey.data.x with radio button choices

No, choices can't be dynamic. You can only assign them.

Thanks, Serge
SurveyJS Team

According to the documentation https://surveyjs.io/Documentation/Library/?id=surveymodel#data
the survey.data property is

An object that stores the survey results/data. You may set it directly as { 'question name': questionValue, … }

you can just write

JavaScript
survey.data.x = [ "item1", "item2" ]

in case of "x" is a name of checkbox question

You are talking about a radiogroup question. Radiogroup question can store only one choosen item:

JavaScript
survey.data.x =  "item1";

If you want to set an array of possible options for a radiogroup question (probably the https://surveyjs.answerdesk.io/ticket/details/t682 question), you should use the choices property (https://surveyjs.io/Documentation/Library/?id=questionradiogroupmodel#choices)) of a question, as illustrated in this sample - https://plnkr.co/edit/DpqFyFynZaOQEQLtFmA0?p=preview

Thanks, Serge
SurveyJS Team