The very fact that he is shown as 8/8 and turned up with A8o in a 3bet pot shows you that your sample size is wayyyy too small. Super loose players start to show pretty early (like maybe 10 hands). The distinction between semi-loose and very tight is not made until much later. You played this hand well and had you folded at any point it would have been a mistake (even if you could see his stats after 14 hands).