Can be used, but does not support fast charge. Oneplus 9r does not support Huawei's fast charge, because this model of OnePlus does not support Huawei's fast charge agreement, so it can not use Huawei's fast charge, which is normal, the fast charge agreement of various brands can not be universal, OnePlus can only support his own fast charge agreement, so he can not use Huawei's fast charge agreement.
You can charge the OnePlus phone.
However, if the charging protocol is not supported, it will be charged with a maximum 5V\/2A 10W charging power, and will not stimulate fast charging.