I went to a public primary school and a catholic high school.We were taught scripture when we were in primary school by scripture teachers that would come to our school once a week....Don't know about that now though.
While Catholicism is taught in the catholic high schools part of our HSC was to learn about other religions such as buddhism ,judaism etc...
While I am a practising catholic I also find Buddhism an interesting religion.
So I think either way your child will have some degree of learning about jesus whether it be in the public or catholic system..