How to play with autistic son

So my son is 2 and we are getting him checked for autism soon but my husband and I already have a gut feeling that he is somewhere on the spectrum. My question is in the title but I am really struggling with feeling connected to him when it comes to playing.

He mostly loves lining up his cars and pushing them around or he will gather all his toys into a corner. He does other things like splashing in his water table or playing with play-doh but I am just worried we aren’t connecting with this kind of play.

If you have any advice I will happily take it. Thank you