Are stores that sell cool custom clothes, for example like a long sleeve t-shirt with Japanese words on it

There's a Spencer's novelty store. It might have what you want. Westfield is more of a conventional mom and dad mall with a JCPenney and Macy's.

I haven't seen anything like that at Westfield Broward, as there aren't a lot of niche stores there. You might check Pembroke Lakes mall- there were a couple possible stores there last time I visited. Otherwise, your best bet is probably online.

There are stores there that offer younger people clothes. As far as Japanese words, i couldn't be 100% sure, but definitely worth a look