To be aligned with your higher self, with source energy, with the universe or what have you, is a term I borrow from Esther Hicks. It simply means when you are not putting any resistant or negative thoughts or vibrations into your being and you are in a purely receptive and creative state. This is you at your most powerful and your truest form.
With regards to numerology, when I’m doing readings or discussing the numbers and traits in general, I tend to refer to the “good” traits of such number as the traits of alignment. For example, a fully aligned life path 8 will be conscientious, good with finances, and ambitious. An 8 that is suffering from misalignment with their higher self is extremely susceptible to greed, an overload of masculine energy, struggles with remaining in control, and spiritual neglect.
Where astrology is concerned, my concept of alignment closely follows. The aligned Libra is personable, diplomatic, confident, and aware of their sex appeal. The misaligned Libra will fall prey to vanity/narcissism, will find themselves without convictions or morals, and helpless to their need to please and their desire for external validation.