Can an 8 year old boy experience orgasm?

Definitely. People, including children of all ages can experience orgasm. An eight-year-old boy who masturbates can achieve a "dry" orgasm beacause his semen producing glands have not yet developed. Unless is rare case of precocious puberty, in which case could have an ejaculatory orgasm. Fyi, some nannies in victorian times stimulated genitals of baby boys & girls to orgasm to induce post-orgasmic sleep.
Yes. http://www2.hu-berlin.de/sexology/gesund/archiv/gus/childorg.htm apparently, years ago it was considered an appropriate subject for research...