Oh I feel for you Logic.
This happens to my dd too. She uses the public bus service and sometimes (thankfully not too often - but often enough, and generally in winter) the bus just simply doesn't turn up - and this is supposed to be their flagship route
Anyhow for the first year or so she would panic and I'd end up getting the car out to take her (so it cost me money to take her + an hour of my time - half hour there, half hour back). But one day last term I didn't have the car and she had no alternative but to wait for the next bus (20 minutes later, but by that point 10 minutes away) and she found she could still make it to school on time (just!). She would never get this later bus previously as she always panicked, thinking she'd be late.
We pay £500 a year for her bus pass (was £350 last year, but that's another story - price rises and all that
), but she can use the bus as often as she likes on which ever route she likes within their 'patch'.
Can your ds not use a different bus stop, to ensure he can get on?