I’m sorry about your bus experiences and that you didn’t get the support you were looking for from your sponsor.
That being stated, I do want to note that
1. There are always two (or more) sides to every story; and
2. We tend to lose objectivity when we are upset
In this case, you seem to have some strong negative opinions about the bus driver. But your ex-sponsor wasn’t completely wrong in the sense that unless you were told certain things and have reason to believe that those things are true, that we should consider the benefit of the doubt.
It’s possible the driver just doesn’t care and maybe there’s something protecting them, as you suggest.
It’s also possible that the driver has some medical or family concerns that is impacting their job performance, in which case those concerns are none of your business and are purely between them and their employer. Sometimes accommodation reasons are quite personal and a person when asked might provide some sort of cover story to avoid disclosing the truth, so even if someone says something it’s not necessarily the truth.
Either way, since you are being adversely affected by the tardiness, and especially given the gap between busses, you absolutely have the right to voice your concerns to the bus company if you so wish, but such should be done while framing things objectively and as concisely as possible (e.g. I take the ### bus at HH:MM from X to Y to get to work, but it has been late (A times in B frequency; details on the range and mode of the lateness if known) and has impacted me (details on how it has impacted your work) . Can you kindly review the situation and help ensure that the HH:MM ### bus will operate on a more timely basis going forward please? Thank you, yournamehere).
Hopefully there will be some sort of resolution soon that might allow you to have a more reliable and normal commute.
In the meantime, while you're taking an earlier bus, perhaps you could use the time you arrive early to explore the area around your work, or maybe you might come to an agreement with your employer on having flexibility in start and end times?