Here Wordsworth is using a metaphor to compare the daffodils to a crowd of people and a host of angels. The word crowd brings to mind an image of the daffodils chattering amongst one another, leaning their heads near each other in the wind. The word host makes them seem like their golden petals are shimmering like golden halos on angels. It is interesting to note that daffodils do have a circular rim of petals in the middle that could look like a halo. Later in the poem Wordsworth uses another simile, saying the dancing of daffodils in the wind is continuous as the stars that shine and twinkle on the milky way.
This line creates the image of the wind blowing the tops of random daffodils up and down in a haphazard matter, so they appear to glint momentarily as their faces catch the sun. This goes along with the next metaphor of the daffodils tossing their heads in sprightly dance. Comparing their movement to a dance also makes me think of swirling, swishing yellow skirts moving in harmony.
It is also interesting how the first image of the wandering cloud contrasts sharply with the second image of the dancingdaffodils. The cloud drifts in solitude slowly and placidly across the sky, whereas the daffodils hurry to and fro in an energetic, lively scramble. This contrast seems to show that looking at the daffodils made the author feel better than he did before, that they cheered him up. This idea is supported by the last line of poem, where he says his heart with pleasure fills, and dances with the daffodils whenever he thinks of them.