Illusionist Bracers (GGR, page 178) Says:
While wearing the bracers, whenever you cast a cantrip, you can use a bonus action on the same turn to cast that cantrip a second time.
Twinned Spell (PHB, page 102) Says:
When you Cast a Spell that Targets only one creature and doesn’t have a range of self, you can spend a number of sorcery points equal to the spell’s level to target a second creature in range with the same spell (1 sorcery point if the spell is a cantrip)
Can I Twin cast Booming Blade (SCAG, page 142) as an action and using the Illusionist bracers, twin cast it again as a bonus action? Thus attacking the same 4 targets twice each?