Q9: Here, as elsewhere in the poem, Heaney makes use of compound nouns, which capture significant visual detail. There is, in addition, a use of synecdoche, as the speaker refers to the rat through its particular parts. The 'terror' he describes is communicated, as before, through visceral, instinctive response.
Q10: There is a strong degree of development at the end. The speaker relays a sense of something having been overcome - a childhood fear, perhaps even childhood itself. This is made clear by the simple, abrupt statements inthe final two lines - as if to register the speaker's new-found confidence.