Is my son, who will pass twelfth next year and will be 17 years old in October, eligible to apply for a bachelor degree in Australia next year?

Yes, your son can apply for a bachelor's degree in Australia next year, even if he turns 17 in October. Most Australian universities require students to be at least 17 at the time of enrollment, but some may have higher minimum age requirements for international applicants.

Eligibility depends on the specific university's policy. Some may accept students who are 17, while others require students to be 18 at enrollment.