Almost 4 year old Tantrums in school

[Tucucina]

My son will be 4 years old at the end of Feb....he's also an only child.  He's been acting up in school. He goes to a Montessori school where children learn independently through a series of "jobs" but they have strict rules in place.  Since he was a baby he has never stopped moving...doesn't sit still much but is very happy and pleasant until lately.  Instead of doing his own jobs at school, he messes with other children's ones and just wants to socialize.  He also thinks he's a comedian.  He likes to mess up other kids work and he thinks he's funny and just playing...he runs and jumps around and likes to be a clown.
I spoke to his peditrician and she thinks it's normal behavior for his age.  His teacher thinks otherwise...I guess he doesn't finish his "jobs", stops mid stream and goes and shows his friends what he is doing...etc. etc...He needs to be constantly redirected.  The teacher never said but inferred that he may have signs of adhd.  I came right out and told her if she thinks this he can not be tested until age 5...
And as of late, he's been randomly knocking into children and hitting them...not malicously but he thinks he's funny.  The teacher and assistants then put him in time out and he gets very angry. He kicks the teachers...and knocks his head into them...and has scratched once.  He went to bite but never bit.  This has happened about 4 times now in the last 2 months.  He also has an issue with snack...the snack is available for the kids to do and make as one of their jobs for about 2 hours each morning...he forgets to get it and when they put it away he has a fit so they put him in time out and trantrum occurs.  I've asked the teacher to give him a heads up that it will be put away and today she told him twice to get snack or it'll be put way and he choose not to get it...and when it was put away he had a fit...then the time out kicking etc. happened again.
She said he doesn't like to be told no.
My husband and I are consistent with our disipline at home.  We do not spank, though, as I don't believe in it. He has consequences to his actions. We do time outs and take away privileages etc.  I am withholding TV today as a consequence to his actions at school today.  I go over rules and explain why we can't hurt people etc.

Not sure if he has a problem or if this is normal or what...
or not sure what to do....I think the teacher is ready to boot him from class.

Wondering if a child with ADHD shows more signs of tantrums etc.  Also, he did not have a tantrum until he was 3 plus...before that he was super easy going and happy...but again never stopped moving.  He rarely does them at home...he had one the other day in public but I redirected him and he seemed to calm down after 10 minutes...

Worried about him...

PS I took him to the movies yesterday to see if he could sit still - he did for 40 minutes and then got figety and had a hard time sitting still afterwards...

[Sandman2]

  Well your son is still only 3.  He obviously stands out from the other kids in his class.  The question is why.  How old are the other kids?  Are they mainly girls?  If he is the youngest kid in the class, or if the class is mainly female - this could/should be expected.
   I can definitely tell you that any punishment that you do at home for what he did at school is not only a huge waste of time, but only adds to the problem.  Children at his age  need immediate consequences.  To punish him for something he did hours earlier (and I can guarantee you, he either has no memory of or won't remember tomorrow)  will never work.  
  I do think that you need more information on ADHD.  Not to say that he has it.  But a child with ADHD can focus (actually hyperfocus) on something they like.  A book I recommend a lot because it covers so much ground in an easy to read format is,
        "The ADD/ ADHD Answer book," by Susan Ashley.
   My guess is that being an only child and being only 3 he is still learning proper behavior.  You can help with that at home.  Check out the post by specialmom in this link and you will find a ton of ways to help him - http://www.medhelp.org/posts/Child-Behavior/Anger--frustration-mangement-for-my-5-year-old/show/1410486
     Also both you and his teacher need to be aware that it takes about 3 weeks of consistent immediate,reinforcement for a child to change their behavior.  If the consistency is lacking, so is the behavioral change.  Hopefully, I have covered both sides of the coin for you. If you have any more questions, please post.

[Tucucina]

anybody out there have any ideas?