My understanding is that if you re-acquire Philippines citizenship, you would automatically lose your naturalized Chinese citizenship.
The special interpretation of Article 9 applicable in HK was intended to apply to HK-born ethnic Chinese. The reason why it was necessary was because China has always regarded the ethnic Chinese population of HK as Chinese citizens.
If Article 9 was strictly interpreted, the ethnic Chinese population born in British HK, before 1997, would have automatically lost (or never had) Chinese citizenship, since they were British nationals. And also most HK-born Chinese had acquired BNO - legally a form of British nationality, even if it's not worth the paper it's printed on - of their own free will in the 1990s, which would fall foul of Article 9. Add to that the fact that many HK-born Chinese had acquired other foreign nationality (eg US/Canada/Australia) before returning to live & work in HK......and you end up with a situation where a significant proportion of the HK Chinese population would fall foul of Article 9.
That's why the Chinese government brought in the "Explanations concerning the Implementation of the Nationality Law of the PRC in the HKSAR" which effectively exempts HK-born ethnic Chinese from Article 9 and turns a blind eye to any foreign nationality that they may have, since China has always regarded them as Chinese citizens by default (and paragraph 1 of the "Explanations" emphasizes this). It was not intended to allow dual nationality under the CNL to foreign nationals.
Of course, you can renounce then reacquire your original nationality without telling, but if they find out then it's possible you could fall foul of Article 9. I would suggest seeking definitive advice from HK ImmD or an HK immigration lawyer before going ahead with re-acquisition of your original citizenship.