I would like to know if the secular buddhism could be considered a religion. I have started to study about it a while ago and I think it's make much sense to me, could I consider me a buddhist, even though I don't believe in some of traditional buddhism beliefs?
Secular Buddhism is loosely associated movement of authors and teachers, Stephen Batchelor is one good example. It isn't an institution, so there isn't any well define orthodoxy to appeal to about what it exactly is. Roughly, Secular Buddhism attempts to do Buddhism in a way that is compatible with ideas of the European Enlightenment and modern science.
Religion is one of those difficult to define words. Dictionary definitions often appeal to similarity to Christianity, which isn't a useful definition here. In the case of Secular Buddhism, I'd say it is a religion on account of it being a philosophical project with goals that overlap with Buddhism's, the end of suffering and what not. I'd recommend looking to Religious Studies (e.g. Religion for Breakfasts youtube channel) for a scholar answer to the question. In Buddhist orthodoxies, anything outside of orthodoxy is heterodox (outer paths, etc) and dividing non-Buddhist things into religion and non-religion isn't an important way of viewing the world.
A common methodology of creating secular Buddhisms is to subtract out the parts of Buddhism incompatible with modern rational thought and science. Yes, this is a form of scientism (using science to form opinions about religious stances) and in my opinion, it is a good thing--usually scientism is a used a slur.
Because there is no institution, nor orthodoxy, Secular Buddhism is very heterogeneous and different authors have used different parts of Buddhism as their starting point and have kept or kicked out different parts. As an internet phenomena, the "Secular Buddhist" podcast, forums etc has a quasi religious belief that the earliest Buddhist texts are already secular and the parts that are incompatible with modern science were later additions. Scholars generally don't agree with that--Buddhism had elements of karma, reincarnation, etc from the first days.
“Religion”, in one sense, involves belief in something not available to be empirically determined.
The ability to arise as a Buddha is one of these things. Again, while ‘enlightenment’ can be fit into many definitions, it is hard to determine empirically if the cessation of suffering is available and if the Buddhist path is effective (the third and fourth noble truths).
Therefore any Buddhism which accepts the four noble truths is not strictly secular, while a system that doesn’t accept the four noble truths is not strictly Buddhist.
Buddhists understand and follow the noble eightfold path:
AN6.63:43.3: The practice that leads to the cessation of suffering is simply this noble eightfold path, that is:
AN6.63:43.4: right view, right thought, right speech, right action, right livelihood, right effort, right mindfulness, and right immersion.
AN6.63:44.1: When a noble disciple understands suffering in this way … they understand that this penetrative spiritual life is the cessation of suffering.
The noble eightfold path starts with right view:
MN117:6.1: And what is right view?
MN117:6.2: Right view is twofold, I say.
MN117:6.3: There is right view that is accompanied by defilements, has the attributes of good deeds, and ripens in attachment.
MN117:6.4: And there is right view that is noble, undefiled, transcendent, a factor of the path.
MN117:7.1: And what is right view that is accompanied by defilements, has the attributes of good deeds, and ripens in attachment?
MN117:7.2: ‘There is meaning in giving, sacrifice, and offerings. There are fruits and results of good and bad deeds. There is an afterlife. There are duties to mother and father. There are beings reborn spontaneously. And there are ascetics and brahmins who are well attained and practiced, and who describe the afterlife after realizing it with their own insight.’
MN117:7.3: This is right view that is accompanied by defilements, has the attributes of good deeds, and ripens in attachment.
MN117:8.1: And what is right view that is noble, undefiled, transcendent, a factor of the path?
MN117:8.2: It’s the wisdom—the faculty of wisdom, the power of wisdom, the awakening factor of investigation of principles, and right view as a factor of the path—in one of noble mind and undefiled mind, who possesses the noble path and develops the noble path.
MN117:8.3: This is called right view that is noble, undefiled, transcendent, a factor of the path.
You ask about secular and tradition. In that regard, perhaps the words of the Buddha might serve here:
MN60:4.1: “So, householders, is there some other teacher you’re happy with, in whom you have acquired grounded faith?”
MN60:4.2: “No, sir.”
MN60:4.3: “Since you haven’t found a teacher you’re happy with, you should undertake and implement this guaranteed teaching.
Many Buddhist traditions exist. Some will speak to you and others won't. Study the words of the Buddha directly, be sensible and see for yourself:
MN80:16.4: Nevertheless, Kaccāna, leave aside the past and the future.
MN80:16.5: Let a sensible person come—neither devious nor deceitful, a person of integrity. I teach and instruct them.
MN80:16.6: Practicing as instructed they will soon know and see for themselves,
MN80:16.7: ‘So this is how to be rightly released from the bond, that is, the bond of ignorance.’
According to the dictionaries: "Secular" and "Religious" are Antonyms.
According to the suttas: It is a wrong view. (diṭṭhivipatti)
Some or all points of 10-fold kammic right view (Kammassakatanana Sammaditthi) are not believed or looked down by the secular Buddhists.
‘There’s no meaning in giving, sacrifice, or offerings. There’s no fruit or result of good and bad deeds. There’s no afterlife. There are no duties to mother and father. No beings are reborn spontaneously. And there’s no ascetic or brahmin who is well attained and practiced, and who describes the afterlife after realizing it with their own insight.
Reference: Natthidinnasutta, Vipattisampadāsutta, Sāleyyakasutta, Apaṇṇakasutta