What does 'a bien tout' mean?

As I understand you question:

"as, a" are forms of the verb "avoir", (to have)

tu as (you have), il / elle a (he, she has)

"bien" means well; and "tout" means all.

"tu as bien tout compris ?" is a standard expression in French, meaning "did you undertand it all?"

"tu as bien tout / tu as bien tout pris / tu as bien toutes tes affaires ?" can be translated as "do you have it all / did you take it all / do you have all your stuff?"

It could be a misspelling of - à bientôt - see you soon