These stanzas form one sentence. They contrast with what has gone before.
However introduces the turning point in stanza 6.
The speaker’s previous confidence is waning and is replaced by insecurity:
...I am obscurely worried...
obscurely suggests he doesn’t understand why. It is also a more adult word - contrasting with the childish tone of stanzas 1 to 5. Possibly the speaker is growing up.
This anxiety is not completely new. The phrase
as usual confirms.
...matters of procedure, the protocol of travel...
Here again adult phrases are used. It seems that it is things that suggest the responsibilities of the adult world, such as when to press the bell on the bus, that unnerve the small boy.
The proud confident tone from before is now reduced to secretive insecurity:
...whispering, Are ye sure? Are ye sure?
The repetition here emphasises the uncertainty and doubt. The use of
ye returns us to the language of the boys as children. This juxtaposes with the adult language around it and reflects the image of small boys out of their depth in adult surroundings.