Huawei just announced that it started seeding the latest version of its custom UI - EMUI 9 based on Android 9.0 Pie. But for now, it's only available in China so the international Huawei P20 and P20 Pro owners will have to wait a bit longer. Probably not that much, though.
For now, there's no word on when the new update will hit the international variants but it probably won't take that long since the Chinese stable version is currently rolling out.
Source (in Chinese)
will it arrives in p20 lite
Mate10 Pro Single SIM -> 21.12.2018 Mate10 Pro Dual SIM -> 21.12.2018 Mate RS Porsche Design -> 18.12.2018 P20 Single SIM -> 18.12.2018 P20 Dual SIM -> 18.12.2018 P20 Pro Single SIM -> 19.12.2018 P20 Pro Dual SIM -> 8...
What about update for midrange phone?, all article said only with kirin 9xx that get constan update