My twins will be 9yrs old in November and don't look anything alike. They were ICSI. DD2 is quite small for her age and in fact the girls at gymnastics thought she was only about 6yrs old! She has brown hair and wears glasses. While DD3 is quite tall for her age and has blonde hair. Apart from their hair colour and difference in size they also look very different.
They look so different that new teachers/student teachers have unable to pick them as being twins when told there are twins in the class.
They don't even really look like sisters unless you see DD1 with them and then you can actually see bits of both of them in DD1.