Simply put, tones are features and variations in pitch quality.
There are six tones in Cantonese. Others list up to nine, even eleven tones.
When people talk about nine Cantonese tones, the extra three tones all derive from the ‘entering’ tone of Middle Chinese, which occurs with finals ending in /-p -t -k/. Since these three tones and other six are complementarily distributed, they can be merged together. This is the reason Jyutping has six tones.
As to the tenth and eleventh tones, they too come from the original six. Beginners of Cantonese do not have to learn the specifics just yet.
Moreover, Jyutping and Hanyu Pinyin treats tones differently. Unlike the latter, where tone marks are placed atop main vowels, Jyutping uses tone numbers placed after the syllables. While the use of tone numbers is similar to the commonly used nomenclature of Putonghua tones, for example ‘first tone’, ‘second tone’, etc., the tones of Cantonese and Putonghua are not the same. Even when comparable, they are at best reference points that are not at all exact.
We will describe the /1/ to /6/ tones of Cantonese in 3.1 The Six Tones of Cantonese