PolyU
No. You can apply either through JUPAS with your HKDSE results or PolyU directly with your sub-degree qualification directly. However, you are not allowed to apply through both routes in the same academic year concurrently. If you apply concurrently, your direct application to PolyU will not be considered. [i]
[i] Academic Registry, The Hong Kong Polytechnic University. Full-time Undergraduate Programmes For HD/AD graduates – Frequently Asked Questions. Retrieved from: https://www51.polyu.edu.hk/eprospectus/ug/non-jupas-adhd-grad/faq [Accessed: 9 Jul 2020]
CityU
No. If you have applied for admission through JUPAS, you should not submit another application to CityU for any programme under JUAPS. All such direct application will not be considered. [ii]
[ii] Admissions Office, City University of Hong Kong. Frequently asked questions (Undergraduate Programmes). Retrieved from: https://www.admo.cityu.edu.hk/?category=faq&view=showall [Accessed: 9 Jul 2020]