1) The chances are this is also linked to your personnality, and those are the most difficult to change.
A good start would be this tool http://habitforge.com/ to get support and encouragement on creating a new habbit of being on time. You will therefore make it fun to be on time with notes from people around the world!
2)Now, it is all about willpower. If you want to, you can. The satisfaction you get when you take control of what you decide to achieve is just the best. It is a mindset shift, don't expect an answer from outside, it is only if you decide to make it happen and do it.
Think about what it means for you: do people think you are reliable? do people trust you? do people think you are courageous? do people think you are strong / weak? do people think you are hard worker who merit a promotion? just taking exemples here, but you need to find what will make you see this behavior as inacceptable, this will be the trigger of you not accepting this for yourself and want to make a change. You have the resources to make it happen and the esteem people have for you when you say you will make a change and really do it / maintain it is just super high. Also you would be surprised by how much if you share this goal for you and ask your close ones to help you and encourage you, you will get a lot of support, recognition and respect from people.
The above is based from my personal recent experience to find work life balance. A struggle for 5 years, I was blaming it on the work load. I got a coach and I hated our first session because she made me feel soooo bad about me not making the choice, that the only problem was me. While I thought a coach was someone to give you the tool / solution to try, the coaching method is actually about making you pass this point of inacceptance of your own behavior / habbit. This trigger point is not a nice experience because you are faced with your own responsibility (I actually cried at that session) but this was the trigger and it worked. Because then I had decided I would make a change, and that I am responsible for it, and that excuses are for the weak. It is all about willpower and courage, and I did it. It now reflected super positively cause I am taking back control over my own life on all aspects, I chose high aspirations and chose to achieve my goals...
I sincerely wish you just the same :)
Hope this will help