Does my iguana have to be in a cage?

well i just got a adult ig from a friend..He wasnt verywell kept, and since i met his ig we always had a connection, so my friend dicided to give him to me. i now have him home and i really dont want to put in in a cage..i have a huge open topped XLrubbermade twith a large drift wood inside that goes half way up my wall, and he seems to love being there, i have had him for 2 days now an he hasnt tryed to escape...can i just use my room as his habitat???