We can use either the infinitive without to or the -ing form after the
object of verbs such as hear, see, notice, watch. The infinitive
without to often emphasises the whole action or event which someone
hears or sees. The -ing form usually emphasises an action or event
which is in progress or not yet completed.
He saw her drive off with a young man in the passenger seat. (The speaker observed the whole event.)
Maria heard him coming up the stairs towards her room, and felt scared. (The action was in progress, happening, but not completed.)
We use the present simple to talk about things that happen regularly, habitually, continually or things that are generally true
The two boys play in the park every saturday - regularly
The two boys usually play in the park - habitually
These two boys play in the village football team - continually
Boys play football - generally true
The continually and generally true usages don't work very well with play- see the link for better examples.
Compare that with are playing, which implies some continuous action that is taking place now:
There are two boys playing in the park
This means that, right now, two boys are in the park: they have been playing for a while, and it seems likely that they will continue to do so for a while.
Best Answer
I’d say my hobby is playing basketball because it’s taking place now in the present, has been for some time in the past and may be in future.